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Sky Watchers Teachers’ Guide

Weather Resource

PDF version – 8.06 MB

Acknowledgements

Project Management: Victoria Hudec (Outreach Officer: Ontario; Sky Watchers National Coordinator)
Author and Custom Artwork: Nicole Lantz (Sprout Educational Consulting)
Photography: George Lantz (Vision Photography), Victoria Hudec and iStock
Diagrams: Nicole Lantz (Sprout Educational Consulting)

Special thanks are extended to Julie Turner and Environment and Climate Change Canada staff across the country for the original Sky Watchers Guide to Weather. We would also like to thank the teachers, students, and educational psychologists in the Halifax Regional School Board and Colchester East-Hants Regional School Board for their input on publication design. Also, thanks to Hannah Thomas and Lisa Vitols for their assistance in the editing process.

Disclaimer

Her Majesty is not responsible for the accuracy or completeness of the information contained in the reproduced material. Her Majesty shall at all times be indemnified and held harmless against any and all claims whatsoever arising out of negligence or other fault in the use of the information contained in this publication or product.

Third-Party Materials

Some of the information contained in this publication or product may be subject to copyrights held by other individuals or organizations. To obtain information concerning copyright ownership and restrictions, please contact:

Environment and Climate Change Canada
Public Inquiries Centre
7th Floor, Fontaine Building
200 Sacré-Coeur Boulevard
Gatineau QC K1A 0H3
Telephone: 819-997-2800
Toll Free: 1-800-668-6767 (in Canada only)
Email: ec.enviroinfo.ec@canada.ca

ISBN: En56-257/2015E-PDF
Cat. No.: 978-0-660-02002-0
Sky Watchers Teachers’ Guide - Weather Resource

Unless otherwise specified, you may not reproduce materials in this publication, in whole or in part, for the purposes of commercial redistribution without prior written permission from Environment and Climate Change Canada’s copyright administrator. To obtain permission to reproduce Government of Canada materials for commercial purposes, apply for Crown Copyright Clearance by contacting:

Environment and Climate Change Canada
Public Inquiries Centre
7th Floor, Fontaine Building
200 Sacré-Coeur Boulevard
Gatineau QC K1A 0H3
Telephone: 819-997-2800
Toll Free: 1-800-668-6767 (in Canada only)
Email: ec.enviroinfo.ec@canada.ca

Photos: © iStock

© Her Majesty the Queen in Right of Canada, represented by the Minister of Environment and Climate Change, 2016

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Pedagogy

The newly adapted Sky Watchers Teachers’ Guide has a number of pedagogical features to make a seamless transition to your classroom.

New Organization

Each section of the newly adapted Sky Watchers Teachers’ Guide is organized to better reflect processes and themes in Canadian provincial and territorial curricula. These curricular themes are then tied to weather, severe weather, Air Quality Health Index, UV Index, and other expertise Environment and Climate Change Canada (ECCC) has to offer.

Description

Description

A graphic organizer showing boxes that the student must fill in before and after the one minute reading.

Activating Prior Knowledge

A trigger question starts each section. This can be used to start a discussion or brainstorm to get students thinking about the topics that lie ahead.

Six Processes are Highlighted Throughout the Text

 Collaboration and community
Collaboration and community
 Using a variety of sources
Using a variety of sources
 Leveraging technology
Leveraging technology
 Collecting data or making observations
Collecting data or making observations
 Predicting
Predicting
 Classification or comparison
Classification or comparison

Graphic Organizers

Two ready-to-print graphic organizers provide students with a framework for assembling ideas as they work through the demonstrations and instructions for building weather instruments.

Activities at a Glance

The best and most relevant demonstrations and weather instrument activities were hand-picked for the newly adapted Sky Watchers Teachers’ Guide. These are now integrated into the text, giving you at a glance ideas for hands-on participation as you review weather topics. You will also notice new questions that help make the demonstrations more interactive and valuable for use in the classroom.

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Graphic Organizers

Building a Weather Instrument

1. Before you build it:

Substitutions/changes to the design:




Science involved:

  • air has mass, weight and volume
  • air expands and rises when heated
  • air moves from high pressure to low pressure
  • water vapour becomes liquid when it condenses
  • water evaporates
  • energy is neither created nor destroyed
  • water can be a solid, liquid or a gas

2. As you build it:

What would happen if…

Why do I need to…

3. As you use it:









Current condition:

4. After you use it:

It would be better if…

Next time I would try…

When I compare with another group, I notice…

Demonstrations

1. Draw or write your ideas and observations in the boxes.

I saw, felt, smelled or heard:




I learned:




Science involved:

  • air has mass, weight and volume
  • air expands and rises when heated
  • air moves from high pressure to low pressure
  • water vapour becomes liquid when it condenses
  • water evaporates
  • energy is neither created nor destroyed
  • water can be a solid, liquid or a gas

Science involved:

  • seasons
  • climate
  • wind
  • clouds
  • ultraviolet radiation
  • air quality
  • humidex
  • humidity
  • precipitation
  • severe weather
  • fronts
  • air pressure

2. Compare two things:

intersecting circles

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Section 1 Energy

Prior Knowledge

What do you know about the sun, how its energy reaches you and how ozone is involved?

Sunset

Description

Bright orange sun setting over the Atlantic Ocean. The sun provides heat and light energy to the Earth.

Section Summary

The sun provides heat and light energy to the earth. Some of the energy that reaches the earth passes through the atmosphere. This visible and invisible radiation reaches different parts of the earth at different times. It also builds protective ozone high in the atmosphere and polluting ozone down at ground level. The sun’s energy, and other factors like altitude and the air mass over your region, affect daily temperature and ultraviolet (UV) ratings.

There are direct and indirect ways to measure how much heat or light energy is in a certain location. Thermometers and UV meters can collect useful information for making everyday choices.

Everything on earth is affected by the energy from the sun. It influences our natural and built environments.

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1.1 Read with Understanding: Energy

Energy From the Sun

The story of weather starts with the sun, which provides heat and light energy to the earth.

The sun’s energy travels 150 million kilometres to the outer edge of the earth’s atmosphere. The sun radiates energy in short waves to the earth but clouds, dust and water vapour in the atmosphere deflect about half of that energy back into space.

The energy that reaches the earth is either visible light or invisible radiation. One form of invisible solar radiation is ultraviolet or UV. It has a shorter wavelength than visible light but carries more energy. UV is classified into three types: UV-A, UV-B and UV-C. Much of the sun’s UV-A reaches the earth’s surface, whereas most of the UV-B, and all of the UV-C, are filtered out by the earth’s atmosphere, primarily by the ozone layer.

The ozone layer is produced naturally about 15 to 35 km from the ground, high up in the atmosphere. A cycle of forming, then breaking up ozone molecules, maintains a natural balance of high-altitude ozone, protecting us from harmful UV radiation. This protection is best when there is a lot of high-altitude ozone, and worst when manufactured products and greenhouse gases, such as chlorofluorocarbons (CFCs), react and destroy the ozone layer. The thicker the ozone layer, the more UV it can absorb.

ozone layer

Description

A drawing depicting the Earth surrounded by the ozone layer with UVA, UVB and UVC rays coming from the sun and penetrating the ozone layer. The ozone layer absorbs some but not all types of ultraviolet radiation.

Ozone is also produced at ground level, but here it is harmful to health, rather than protective. Ground-level ozone is formed when pollutants such as nitrogen oxides (NOx) and volatile organic compounds (VOCs) react using this energy from the sun. As a result, ground-level ozone is higher when there is more NOx from burning fossil fuels and more VOCs from the evaporation of liquid chemicals. Since sunlight is required to form ozone, the concentrations in the air are normally higher in the summer, when temperatures are warmer and the sun’s rays are stronger.

Once the sun’s visible and invisible energy passes through the atmosphere, it is absorbed by the land and water. Here, it is converted to heat to warm the earth and the air above it, as well as melt snow and evaporate water. The earth radiates this heat back as long-wave energy, which then warms the air above.

Because the earth moves, not all areas receive the same amount of energy at the same time. Also, even if the amount of energy received is the same, not all surfaces on earth absorb the same amount of energy.

Emissions

Description

Emissions filling the air around an industrial site. Ground-level ozone is higher when there is more NOx from burning fossil fuels and more VOCs from the evaporation of liquid chemicals.

Mist

Description

Mist hanging over a lake at night. At night, the Earth continues to radiate heat, even though it receives no energy from the sun.

The Earth’s Rotation Causes Night and Day

The earth rotates on its axis every 24 hours, creating night and day. During the day, the earth receives more energy than it radiates back, so it warms up. At night, however, the earth continues to radiate heat, even though it receives no energy from the sun. Consequently, the earth cools down. This cooling process continues until after sunrise, which is one of the reasons why sunrise often has the lowest temperature for the day.

The Earth’s Orbit and Tilt Cause Winter and Summer

The earth revolves around the sun every year. During the earth’s orbit, some regions receive more of the sun’s energy than others.

The earth is also tilted on its axis at an angle of 23½ degrees. Without that tilt, the sun would shine directly over the equator all year and there would be no seasons. Instead, the sun’s energy hits different parts of the earth at different angles, affecting the amount of heat any one part of the earth receives. This unequal heating also sets the air in motion, creating global wind belts.

Canadians do not need to be reminded about the effect that the seasons have on temperature. Canada has its warmest weather when the sun is over the Northern Hemisphere. The sun passes over the equator around March 21st on the way north to the Tropic of Cancer at 23½° north latitude. This is the sun’s northern-most position, which it reaches around June 21st. From here, the sun starts the slow slide south again to the equator, reaching there about September 21st.

During the 6 months the sun is over the Northern Hemisphere, its rays shine down on Canada more directly than they do during the country’s winter months. The sun reaches the Tropic of Capricorn at 23½° south latitude around December 20th, when it starts moving north again to the equator.

North and South

The latitude of a region affects how much of the sun’s energy it receives. The countries around the equator receive more of the sun’s direct energy than those that lie farther north or south. That is because the sun’s rays are almost perpendicular to the earth’s surface at the equator. To reach areas closer to the poles, such as Canada, the sun’s energy must travel at an angle and pass through more of the atmosphere. Consequently, by the time the sun’s rays reach Canada, they are weaker, more spread out and diffuse than the rays that hit the earth around the equator.

Earth and atmosphere

Description

A drawing that depicts the Earth and its atmosphere, and the angle that the sun’s energy must travel to get to the North Pole and to the Equator. Countries around the equator receive more of the sun’s direct energy than those that lie farther north or south.

Demonstration: What Energy Reaches the Earth’s Surface?Footnote 1

Materials

  • a globe or map of the earth
  • a small flashlight

Method

  1. In a darkened classroom, shine the light directly down on the equator.
  2. Keeping the flashlight at the same height and over the equator, tilt the flashlight so that it shines on the Tropic of Cancer, north of the equator.

Questions

Where do you think the light will be brightest? Can you see its outline clearly? What does the shape of the light look like? How does the area of light change when it is tilted? Does the light cover a larger area? Are some parts of the area lit by the flashlight brighter than others?

Explanation

The shape and the intensity of light changes when it shines at an angle. The earth’s tilt affects the strength of the sun’s rays at different points on the earth’s surface.

Snow melting
Description

Snow melting along the edge of dark pavement. Ice and snow reflect energy whereas pavement absorbs it.

Geography Affects Heating and Cooling

The geography of an area plays a role in its heating and cooling because factors such as material and color affect how a surface absorbs the sun’s energy.

One reason for this is that water heats and cools more slowly than air. For example, coastal communities often have lower summer temperatures and warmer winter temperatures than communities that are farther inland.

A dark-coloured surface absorbs more of the sun’s energy than a light-coloured surface. Ice and snow reflect energy, whereas pavement absorbs it. You may have noticed that cities can experience different heat effects.

Record-Setting Temperatures Across Canada
Province or TerritoryHighest Temperature (°C)Lowest Temperature (°C)
Alberta43.3 Bassano Dam-61.1 Fort Vermilion
British Columbia44.4 Lytton, Lillooet-58.9 Smith River
Manitoba44.4 St. Albans-52.8 Norway House
New Brunswick39.4 Nepisiguit Falls-47.2 Sisson Dam
Newfoundland and Labrador41.7 Northwest River-51.1 Esker 2
Northwest Territories39.4 Fort Smith-57.2 Fort Smith
Nova Scotia38.3 Collegeville-41.1 Upper Stewiacke
Nunavut33.6 Baker Lake-57.8 Sheppard’s Bay
Ontario42.2 Atikokan & Fort Frances-58.3 Iroquois Falls
Prince Edward Island36.7 Charlottetown-37.2 Kilmahumaig
Quebec40.0 Ville Marie-54.4 Doucet
Saskatchewan45.0 Midale and Yellow GrassTable note a-56.7 Prince Albert

Heat Waves

Despite the country’s reputation as the land of snow and ice, Canada has heat waves. Environment and Climate Change Canada (ECCC) defines a heat wave as 3 or more consecutive days with temperatures of 32°C or higher. Most heat waves in Canada last about 5 or 6 days.

The worst heat wave on record was in July 1936. The heat rolled into the Prairies from the American southwest in early July and spread into Ontario. Temperatures climbed to 44.4°C at St. Albans in Manitoba and to 42.2°C at Atikokan and Fort Frances, Ontario. Those records stand today. The heat wave lasted a week and was directly or indirectly responsible for the deaths of 780 people in Canada.

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1.2 Observe

Measuring Energy from the Sun

There are direct and indirect ways to measure how much heat or light energy is in a certain location. Two measures are of particular interest because they affect everyday choices: temperature and UV radiation. Temperature is a measure of the average heat energy in the air. UV radiation is only one part of the sun’s invisible energy that reaches the earth’s surface, but an important one.

Thermometer

The substance inside a thermometer reacts to temperature changes. This may be a liquid or a metal coil. Thermometers using a liquid are faster to respond to temperature changes than those with a metal coil. This is due, in part, to the sheer mass of the metal coil, and to the fact that the air flow over the coil is reduced.  

In Canada, we use metric units called degrees Celsius (˚C). Some thermometers can be set to track the current, maximum and minimum temperatures. Others only indicate the current temperature.

Hang a thermometer at eye level and away from direct sunlight. A shady, secure, grassy area on the north side of a school may be the best spot. Try to allow for air to flow across the unit. This will improve the reaction time of the thermometer to changes in air temperature.

If you do not have a secure area for permanent instrument exposure, store the thermometer in a classroom and hang it outside for 30 minutes before you take a reading.

Building a Weather Instrument: Thermometer

Materials

  • small, narrow glass jar with cork or stopper
  • cooking oil
  • a sealant (e.g., petroleum jelly, candle wax or modelling clay)
  • several drops of food colouring
  • clear narrow drinking straw at least 15 cm long
  • eye dropper
  • water
  • an index or recipe card about 8 cm by 13 cm
  • thermometer for reference

Note: The width of the straw and the amount of liquid in the jar will affect how quickly and accurately a thermometer will respond. With a narrow straw, a smaller volume of water is required to noticeably raise the level in the straw.

Instructions

  1. Fill the glass jar with water and add a few drops of food colouring to make the water visible.
  2. Cut a hole in the stopper or cork, just large enough to fit the straw.
  3. Place the stopper in the jar and insert the straw through the hole.
  4. Add more water, but this time through the straw and until the water is about one quarter of the way up the straw.
  5. Seal the straw into the stopper and the stopper onto the jar using either the petroleum jelly, modeling clay or candle wax.
  6. Finally, put a drop of the cooking oil into the straw so that the oil sits on top of the water. The oil prevents the water from evaporating.
  7. Attach the index card to the straw. Allow the thermometer to settle for two or three hours.
  8. Use the reference thermometer to calibrate your home-made thermometer. To do this, note the level of water in the straw and mark a line on the card. Beside the line, record the temperature shown on your reference thermometer. Repeat this process over the next several days.

Why it Works

This thermometer is based on the principle that water expands when heated and contracts when cooled. It takes a long time to respond because the entire jar of water must adjust before it will register the new temperature.

UV Meter

A UV meter will measure the burning effect of UV radiation on human skin and express it using the UV Index. Many meters turn on automatically when exposed to sunlight. Consult the instruction manual to determine if the model should be held flat or on an angle. In either case, hold the meter about 30 cm in front of your body and out of the shade.

It is easiest to compare UV levels from 11 a.m. to 4 p.m. on sunny days in May or June. For best results, move away from buildings that might reflect additional light. Make sure your fingers or other objects do not shade the meter, particularly the sensor window on the front edge of the meter. Try not to touch the sensor window as this may scratch or streak the window and affect the readings.

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1.3 Predict

The easiest way to get information about UV and temperature is using ECCC’s weather website at weather.gc.ca. You can check the website daily to gather data for graphing or to do community comparisons.

Weather Reports: Temperature

Although it is easy to measure temperature with a thermometer, it is tricky to forecast it. ECCC feeds current weather conditions into complex computer models to predict temperature. Mathematical equations then predict how the weather may change over time because of wind direction, sky conditions, precipitation, how close the forecast area is to large bodies of waters, or the arrival of a new air mass into the region.

How did they predict temperatures before computer models? A simple start was to forecast the same temperature tomorrow as was observed today. Then, meteorologists had to ask a lot of questions about air masses, cold or warm air movement, expected sunshine or cloudiness, wind direction and strength, and whether the wind was blowing off the land or the water.

Nowadays, meteorologists have to be computer savvy to ensure that mathematical equations and weather models consider all of these things.

Weather Reports: UV Index

The UV index was developed by ECCC to inform Canadians about the strength of the sun’s UV rays. The higher the number, the stronger the UV rays, and the greater the need to protect yourself.

Canada was the first country in the world to issue daily UV index forecasts for major cities. Latitude, cloud cover and precipitation are factored into the local UV index. The UV Index is reported when the index is 3 or above.

ECCC’s computers produce a daily UV Index forecast for many Canadian communities based on the angle of the sun at midday, predictions of the ozone-layer thickness, observations at Canadian ozone-monitoring stations and the forecast cloud cover. The UV Index forecast is a prediction of the maximum UV Index value for that day (morning forecast) or the next day (evening forecast). Under clear skies, this will occur at midday when the sun is at its highest point in the sky. In the summer, this generally occurs from 1 to 2 p.m.

For more information about the UV Index, go to The UV Index and Ozone.

Weather Reports: Air Quality Health Index (AQHI)

Another index, the Air Quality Health Index (AQHI), gives information to the public about air pollution. One pollutant included in the AQHI is the amount of ground level ozone produced using energy from the sun. Since ground-level ozone is invisible, it is useful to have an index that measures air quality and suggests how to adjust activity levels for the conditions.

For more information about AQHI, go to Air Quality Health Index.

Classification: Compare and contrast the UV Index and the AQHI.

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1.4 Reflect

What Does Temperature Mean to Me?

Temperature and Clothing

On cold days, you have probably been told to wear several layers of clothing to keep warm. That is because air trapped between layers acts as an insulator and slows down the loss of heat from your body.

Did you know that the colour of your clothes might affect how warm you feel? Light colours reflect more of the sun’s energy than dark colours, so are cooler to wear on a sunny day. By the same logic, black keeps you warmer in the sun.

Temperature and the Built Environment

Home builders consider the climate of a region when designing the layout of a building. In many parts of Canada, building a house with large windows facing south, for instance, can reduce heating costs. The sun is lower on the horizon in winter so the sunshine pouring in through the windows will partially heat the house. Interestingly, in summer, the sun is more directly overhead so it does not have the same effect.

Classification: What features of a home, building or landscape make good (or bad) sense for heating or cooling? For example, coniferous trees provide shade from the sun and shelter from cold winds.

Afternoon sun

Description

Afternoon sun pouring in through a large, south-facing window. The sun is lower on the horizon in winter, so the sunshine pouring in through the windows will partially heat the house.

What Does UV Mean to Me?

Human Health Effects of UV Radiation

Although energy from the sun is essential because it sustains all life on earth, some forms of the sun’s energy can be harmful.

Skin damage caused by UV radiation is cumulative, whether it comes from the sun, or artificial sources such as tanning beds. Daily exposure to natural or artificial sunlight adds up, damaging the DNA of our skin cells. A tan, like a sunburn, is a sign that the skin has been damaged by UV radiation. If cells cannot repair the DNA, skin cancer can result. The occurrence of skin cancer has increased in Canada at a fairly constant rate over the past 30 years. In 2010, there were roughly 75,500 new cases of basal and squamous cell carcinomas reported in Canada, and about 5,300 new cases of malignant melanomas.

In addition to skin cancers and sunburns, overexposure to UV rays can lead to a weakening of the immune system, eye damage, eyelid cancers, and premature aging of the skin.

Silhouette of plant life

Description

Silhouette of plant life on the edge of a lake. Increased UV exposure in lakes and oceans can damage tiny single-celled plants called phytoplankton that provide food for fish and other animals.

UV Effects on Plants and Wildlife

Ultraviolet radiation not only affects humans, but wildlife as well. Excessive UV-B inhibits the growth processes of almost all green plants. There is concern that ozone depletion may lead to a loss of plant species and reduce global food supply. Some agricultural crops, such as canola, oats, and even cucumbers, show reduced yields at higher levels of UV.

Ultraviolet radiation has an effect on natural communities. Increased UV exposure in lakes and oceans can damage tiny single-celled plants called phytoplankton that provide food for fish and other animals. Sudden, brief UV increases during early spring can damage young vegetation or the eggs of fish and frogs.

UV and the Built Environment

Community planners design for shade around buildings and recreational areas. UV also reduces the lifetime of the construction materials used in buildings.

Staying Protected

It is important to adopt good sun protection strategies at an early age, because skin damage caused by the sun builds up over time. Walking, biking, recreation and sports are great ways to be active outdoors. Simply check and plan for UV as you would check for the weather.

The following is a list of protective measures. Enjoy the sun safely. Protect your skin, protect your eyes.

  • Seek shade or bring your own (e.g., an umbrella).
  • Wear clothing that covers as much skin as possible and a wide-brimmed hat.
  • Wear sunglasses or eyeglasses with UV protective lenses
  • Wear approved UV-filtering sunglasses.
  • Use sunscreen labelled "broad spectrum" and "water resistant" with a sun protection factor (SPF) of at least 30 on skin not covered by clothing. Apply sunscreen generously and reapply often.
  • Avoid getting a sunburn and avoid intentional tanning.

The table below outlines the sun protection actions recommended at different levels of the UV Index.

UV IndexDescriptionSun Protection Actions
0 to 2LowMinimal sun protection required. If outside for more than one hour, wear sunglasses and sunscreen. Reflections can nearly double UV strength.
3 to 5ModerateTake precautions. Cover up, wear a hat, sunglasses and sunscreen if outside for 30 minutes or more. Look for shade near midday.
6 to 7HighProtection required. UV damages skin and can cause sunburn. Reduce time in the sun between 11 a.m. and 3 p.m. Seek shade, cover up, wear a hat, sunglasses and sunscreen.
8 to 10Very HighExtra protection required. Unprotected skin can be damaged and burn quickly. Avoid the sun between 11 a.m. and 3 p.m. Seek shade, cover up, wear a hat, sunglasses and sunscreen.
11+ExtremeMaximum protection required. Unprotected skin will be damaged and burn in minutes. Avoid the sun between 11 a.m. and 3 p.m. Remain in the shade, cover up, wear a hat, sunglasses and sunscreen.

For more information on sun safety, consult Health Canada’s UV Index Sun Awareness Program or the Sun Safety website.

Investigation: Determining the Best Protection From UV

Materials

  • UV meter(s)
  • pencil and pad
  • three (3) different types of fabric (e.g., cotton, synthetic, silk) in the same colour
  • three (3) different colours of fabric of the same type and weight (e.g., black, white, and
  • red cotton)
  • three (3) pairs of sunglasses
  • several leaves and/or types of shade (e.g., buildings, tree(s), umbrella)
  • calculator

Method

  1. Choose a day when the UV Index is forecast to be 6 or greater.
  2. Identify variables and assign to groups, each with their own UV meter.
  3. Make predictions about which materials or shade give the best protection against UV.
  4. Put the samples in a random order.
  5. Take a UV reading with the UV meter in direct sunlight and record the value.
  6. Place each sample, one at a time, on the UV meter over the sensor. Ensure that the sensor is completely covered. Do not touch the sensor with your fingers. To sample types of shade, move the UV meter from direct sunlight to the designated shaded area before taking the reading.
  7. Wait a minute for the UV meter to adjust between samples.
  8. Calculate the percentage of UV transmitted through each type of fabric sunglasses or shade compared to the full sun reading.

UV transmitted (%) = (reading under sample ÷ full sun reading) x 100%
UV reduction (%) = 100% - UV transmitted

Questions

  • Which fabrics give the best protection against UV?
  • Which sunglasses give the best protection against UV?
  • What type of leaf or shade gives the best protection against UV?
  • Why is it important to change only one variable at a time?
  • Why should the samples be in a random order?
  • How would variable cloudiness affect the results?

Explanation

The more of the sky that is blocked by trees and other objects, the lower the amount of UV. In general, denim and polyester protect better than cotton; tight weaves, better than loose; dark colours, better than white; and heavy fabrics better than light. Sunglasses show approximately how well a pair of sunglasses protect your eyes from UV-B. Accurate UV testing for sunglasses can only be conducted by an optometrist or ophthalmologist. UV-A is also harmful to the eye. When buying sunglasses, it’s wise to check the label for the degree of protection from both types of UV.

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What Does Ground-level Ozone Mean to Me?

Human Health Effects of Ground-level Ozone

Exposure to ozone can irritate the nose and throat and cause chest tightness, coughing and wheezing. Increases in ground-level ozone in Canada have been linked to increased mortality, emergency hospital visits and admissions for respiratory problems. In sensitive people, the stress of ozone exposure can be particularly damaging. There is also evidence that ozone heightens the sensitivity of asthmatics to allergens. Other studies on animals have indicated that ozone exposure decreases the ability of the lungs to ward off disease. The effects also include decreased lung capacity, which can impair performance in athletes

Demonstration: How it Feels to Have Breathing Problems When the AQHI is High

Health note: This activity must be voluntary. It is not for high-risk groups! Restricted airflow may cause dizziness or hyperventilation.

Materials

  • juice box straw or other very thin straws

Method

  1. Take 10 normal breaths.
  2. Put the straw in your mouth and plug your nose.
  3. Take 10 breaths again.

Questions

  • What is the difference between breathing normally and breathing through a straw?
  • How would it feel to breathe like this all the time?
  • What do you think would happen if you tried to play sports or run, breathing only through the straw?
  • How could you simulate ground-level ozone in addition to a pre-existing health condition?

Explanation

The straw simulates how air passages constrict, limiting air flow to the lungs of a healthy individual when the AQHI is high or to an individual with breathing difficulties when the AQHI is lower.

Effects of Ozone on Plants

Ozone interferes with the ability of plants to produce and store food. This threatens growth and reproduction and makes plants more susceptible to pests and disease.

Some estimate that the provinces of British Columbia and Ontario each lose millions of dollars per year because of lower crop productivity due to high levels of ground-level ozone. Ozone damage can be seen on the foliage of some potato varieties in Atlantic Canada. Beans, tomatoes, potatoes, soya beans and wheat are all crops that are sensitive to ozone. Trees, which live longer than the plants above, are exposed to ozone year after year. If the effects of exposure add up over many years, entire forests may be affected. This means that plants and animals that depend on the trees to provide shelter are also affected by prolonged exposure to ground-level ozone.

Classification... Compare and contrast ground-level ozone in rural and urban areas. (Rural pollution can be just as bad as urban pollution, depending on a combination of local weather conditions, topography, or the amount of pollution due to long-range transport.)

Peeling paint
Description

Paint peeling off wood siding. Certain types of paints and other coatings are damaged or weakened by ozone exposure.

Ozone and the Built Environment

Materials you use in everyday life can be weakened by exposure to high levels of ozone. Rubber, textile dyes and fabrics, and certain types of paints and other coatings are either damaged or weakened by ozone exposure. Synthetic elastic materials can become brittle and crack, while the textiles and dyes fade faster than usual.

For more information on the effects of ground level ozone, go to Air Quality Health Index.

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Section 2 Water Vapour

Prior Knowledge

What do you know about humidity and clouds, and why we should care about particles in the air?

Puffy white clouds

Description

Puffy white clouds in a bright blue sky. When water droplets or ice crystals condense around particulate matter, it creates clouds.

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Section Summary

Water cycles around the earth as liquid, vapour, or solid ice and snow. Humidity represents the amount of water vapour in the air. As the temperature increases, the air can hold more water vapour. Water starts to condense, or come out of the air, at its dew point temperature. When these water droplets or ice crystals condense around particulate matter, many types of clouds are created at different altitudes. In certain cases when hot, humid air is forced to rise quickly, tall, turbulent thunderstorm clouds are formed.

Weather instruments such as a hygrometer or sling psychrometer can be used to measure humidity and relative humidity. Cloud cover indirectly represents the amount of condensation taking place in the air. It is one of the weather observations collected and plotted on weather maps using an internationally accepted code called a station model.

Canadians rely on weather reports for information that helps inform their day-to-day decisions. In summer this includes the humidex, which indicates how high the temperature feels when combined with humidity.

Clouds are visible using satellite imaging, and give forecasters clues to help track and predict local and regional weather. Forecasters at Environment and Climate Change Canada (ECCC) regularly use satellite imaging to monitor weather systems. They also issue severe weather bulletins to keep the Canadian public advised of weather events that could affect their safety or property.

If folks don’t want to leave it to the experts, they can look around for condensation and humidity clues to predict the weather themselves. However, they should pay attention when there are clues they can’t ignore, like thunder. Thunderstorms come hand in hand with lightning, hail and downbursts, which are serious hazards.

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2.1 Read with Understanding: Water Vapour

The Water Cycle

On Earth, water is constant in quantity and continuous in motion. Little has been added or lost over the years. The same water molecules have been transferred time and time again from the oceans and the land into the atmosphere by evaporation, dropped on the land as precipitation, and transferred back to the sea by rivers and groundwater. This endless circulation is known as the “hydrologic cycle”.

Drawing of the hydrologic cycle

Description

A drawing of the hydrologic cycle showing the processes of condensation, precipitation, transpiration, evaporation and surface runoff. On Earth, water is constant in quantity and continuous in motion.

In this cycle, the energy from the sun evaporates liquid water and sublimates solid water. The heat changes water directly from a liquid or solid to a gas. Plants transpire. They release water as a gas through their leaves.

Water Vapour

People often think of water as a liquid, but Canadians know that water is also solid ice and snow. Likewise, in the hot summer humidity, it is impossible not to feel the water that exists as a gas, or vapour, in the air.

There is always a small amount of water vapour in the air, but warmer air can hold more water vapour than cooler air.

When meteorologists talk about the amount of water in the air, the terms they use most frequently are relative humidity and the dew point temperature.

Relative Humidity

The relative humidity is the amount of water vapour that is actually in the air compared to the amount of water vapour that could be in the air at that temperature. Relative humidity is given as a percentage. For example, a relative humidity of 100% means the air is full of water vapour. It is saturated. Relative humidity of 25% means the air contains one quarter of the moisture that it could hold at that temperature.

Demonstration: From Liquid to Vapour and Back Again

Materials

  • water
  • saucer or shallow bowl
  • tape
  • a healthy houseplant
  • clear plastic bag (light has to shine through bag)

Method

  1. Pour some water onto the saucer or shallow bowl.
  2. Mark the level of the water with a piece of tape.
  3. Place the dish with the water in it on a windowsill for the day.
  4. Wrap the plant (pot and all) in the plastic bag and put it on the windowsill for a few hours.
  5. Predict what will happen to the water and the plant.

Questions

  • Why does the level of the water drop below the tape mark?
  • Where did the water go?
  • Why place the items on the windowsill?
  • What does a plant have to do with the water cycle and weather?

Explanation

Liquid water enters the atmosphere through evaporation. This can happen directly using heat energy from the sun. The evaporation of water through pores on the leaves of plants is called transpiration. Transpiration is essentially a way that water moves from deep within the soil up into the air. Underground water can be drawn up through the roots of plants, through the plants themselves, and released from the underside of plant leaves.

Dew Point Temperature

The dew point temperature is the temperature cool enough for the moisture to condense out of the air, forming dew. For example, if the dew point temperature is 10°C, then the air temperature has to fall to 10°C before it becomes saturated and its water vapour condenses to form water droplets or dew.

That is why dew forms on clear nights when the earth’s heat radiates back into space. The air cools down to the dew point temperature, water condenses out of the air, and dew forms on objects at the earth’s surface such as grass and flowers.

Outline of a spider's web

Description

Dew revealing the intricate outline of a spider's web. The dew point temperature is the temperature at which moisture will begin to condense out of the air, forming dew.

Emissions from a power-generating station

Description

Emissions from a power-generating station. The major sources of particulate pollution are factories, power plants, trash incinerators, motor vehicles, construction activities, wood stoves, fireplaces, forest fires and natural dust blown around by the wind.

Meteorologists use the term dew point temperature even on the coldest winter day, although frost point temperature may be a better name for it. On cold winter days, the water vapour changes from a gas directly to a solid without becoming a liquid first.

Particulate Matter

Clouds form when moisture laden air cools to its dew point and water droplets or ice crystals form around little particles such as dust, pollution and volcanic ash. These little particles are called particulate matter (PM).

Particulate matter is made up of very tiny solid or liquid particles that are small enough to remain suspended in the air. Even coarse particulate matter (PM10) is under 10 micrometres (µm) in size, or 1/8th the size of a human hair. The fine particles (PM2.5) are less than 2.5µm in size. These particles are smaller than a single particle of flour.

Particulate matter includes dust, dirt, soot, smoke and tiny particles of chemical pollutants. The major sources of particulate pollution are factories, power plants, trash incinerators, motor vehicles, construction activity, wood stoves, fireplaces, forest fires and natural dust blown around by the wind.

The amount of particulate matter in the air can be worse in winter from the burning of wood and other fuel to heat houses. In big cities, particulate matter can be worse than in rural areas where there are fewer cars.

Clouds

Particulate matter is so tiny and light that the water droplets or ice crystals that form around it stay up in the sky as clouds. More than two billion of them are needed to fill one teaspoon with water.

Clouds form at different levels in the atmosphere. The air stability and humidity affects their size, shape, and type.

clouds

Description

A drawing of clouds that shows a close-up view of particulate matter inside the clouds, surrounded by a droplet of water. Particulate matter is so tiny and light that the water droplets or ice crystals that form around it stay up in the sky as clouds.

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Naming Clouds

In the early years of the nineteenth century, an Englishman named Luke Howard classified the clouds according Naming Clouds to their appearance and behaviour. Mr. Howard was an apothecary or pharmacist with a keen interest in the atmosphere and all that it contained. He used Latin to name the types of clouds.

Stratus - Stratus means stretched out or layered

Cirrus - Cirrus means curl, lock of hair

Cumulus - Cumulus means heap

Nimbus - Nimbus means rain cloud, cloud burst, shower and clouds

From the Ground Up

Low Clouds

The bases of low clouds begin from 0 to 2 km above the earth’s surface. Depending on the season, these clouds may contain water droplets, ice crystals, or a mixture of both.

Stratus Clouds

Stratus clouds are the low, uniformly dull, gray clouds that hang heavily in the sky. Their bases may cover the tops of hills or high buildings. If it is not drizzling already, stratus clouds are a good sign that precipitation in the form of drizzle may be on the way.

Fog and Mist

These are thin layers of stratus cloud that form at ground level. Like any cloud, fog is composed of millions of tiny droplets of water, or in cold weather, tiny floating ice crystals. The thickness of fog depends on the concentration of water droplets. Weather observers report fog if the visibility is less than 1 km, and mist if the visibility is 1 to 10 km.

Smog

Smog is a brownish-yellow or greyish-white haze in the air, originally named as a combination of “smoke” and “fog”. This haze is a mixture of pollutants made mostly from particulate matter (PM) and ground-level ozone (O3). Other pollutants include sulphur dioxide (SO2), nitrogen oxides (NOx), carbon momonoxideide (CO) and hydrogen sulphide (H22S). Motor vehicle exhaust contains five of the components of smog: carbon momonoxideide, particulate matter, lead, nitrogen oxides, and volatile organic compounds.

Heavy clouds in Halifax

Description

Heavy clouds covering the top of office buildings in downtown Halifax. Stratus clouds are the low, uniformly dull gray clouds which hang heavily in the sky. Their bases may cover the tops of hills or high buildings.

 

Nimbostratus

As the name suggests these are low-lying, dense, gray clouds that may produce continuous rain, or if it is cold enough, snow. These clouds are thicker or deeper than stratus clouds.

Stratocumulus

These clouds have a well-defined rounded appearance and are often organized into rolls with flat bases that have gray or dark gray patches. Stratocumulus clouds are common in late autumn or winter.

Fog covering the base of a suspension bridge

Description

Fog covering the base of a suspension bridge. Fog and mist are thin layers of stratus cloud that form at ground-level.

 

Cumulus

These little, puffy, fair-weather clouds commonly form on a summer afternoon. They usually cover less than half the sky and produce no precipitation.

Towering Cumulus

These begin as cumulus clouds but grow vigorously into rising mounds or towers. Their tops are well-defined and often resemble cauliflowers. The bases are flat and dark. These clouds may produce showers or flurries.

Cumulonimbus

Some clouds extend high into the atmosphere, as high as 14 km and more than 25 km long. These very tall clouds are called cumulonimbus or thunderstorm clouds. Meteorologists call these clouds CBs. Temperatures at their tops are as low as -55˚C, even in the summer.

If you look at this cloud from a distance, it has a well-defined, whitish, anvil-shaped top and a ragged and low bottom. When you look at this cloud from below, it has a dark base with curtains made of heavy rain.

Stages of a Thunderstorm

Cloud types during the stages of a thunderstorm
Description

A drawing that shows the cloud types that form during each stage of a thunderstorm. The first cloud type is cumulus, followed by towering cumulus and then cumulonimbus. Stages of a thunderstorm.

Cumulonimbus clouds form when a parcel of humid air is so warm it rises very far up before it cools enough to reach its dew point. Here, there is a unique combination of strong updrafts (rising air) and downdrafts (sinking air).

As cumulonimbus clouds develop, water droplets bounce around so hard they collide with others, creating ever larger water droplets. Eventually, these water droplets become too heavy for even the strong updrafts to support, and rain falls.

The turbulence in cumulonimbus clouds creates positive and negative electrical charges. Scientists do not know why but, generally speaking, the positive charge develops in the cold upper reaches of a cloud and the negative charge develops in the lower portions of a cloud. This, in turn, induces positive charges in objects on the ground below.

Although air is a notoriously poor conductor of electricity, the electrical charge in the cloud above grows until it overcomes the air’s resistance. Interestingly, even though lightning looks like one bolt hurtling towards earth, it is not. Lightning usually occurs when the electrons holding a negative charge begin moving downward from the cloud to the earth in what is called a step leader. As they get closer to the earth, the negative force of the electrons attracts the positive charge from the earth. This flows upward in what is called a streamer. This streamer or return stroke flows upwards at about 96,000 km/s and at temperatures of 30,000°C, which is six times hotter than the sun.

Demonstration: Warm Air Rises and then Condenses as it Cools

Materials

  • kettle with boiled water
  • clear, heat-proof jar
  • aluminum tray or pie plate
  • ice

Method

  1. Pour 2.5 centimetres of hot water into a jar.
  2. Put ice cubes onto the tray or pie plate and place that over the opening of the jar.

Questions

What happens as the air inside the jar rises and is cooled by the ice?

Explanation

The water vapour in the air condenses onto the cold surface and collects to form droplets.

The same process occurs when lightning travels from one cloud to another. In fact, 90% of lightning strokes flash from cloud to cloud or within the same cloud.

Thunder is the sound produced by the sudden and rapid expansion of the narrow channel of air heated by the lightning stroke. You see the lightning, then hear the thunder because the speed of light is about a million times faster than the speed of sound.

Thunderstorms often change as they travel across the countryside. Lakes and the local terrain may affect the strength, movement and duration of storms. For example, if a thunderstorm passes over hills and ridges, it may grow stronger as it climbs up one side and weaker as it goes down the other. A thunderstorm may grow stronger if it moves over a long stretch of flat land that has been baking in the sun all afternoon, or weaker if it passes over a large body of cool water in the late spring.

Only a small percentage of the thunderstorms during Canadian summers unleash enough energy to produce severe weather: high winds, heavy downpours, damaging hail or tornadoes. Remember, to stay safe during a thunderstorm, when thunder roars, go indoors!

Middle Clouds

Clouds with the prefix alto are middle-range clouds. Their bases usually range from 2 to 6 km above the earth’s surface.

Altostratus

These are gray or blue-coloured sheets of clouds with little texture. They cover most of the sky. In some spots, altostratus clouds may be thin enough to reveal the sun.

Altocumulus

These are white or sometimes gray clouds with rounded bottoms. The clouds may look as if they are arranged in rolls, rounded masses or thin layers. The individual rolls of cloud appear smaller than those in stratocumulus clouds because altocumulus clouds are farther away. Sometimes you can see the sky or the sun between the rolls, but often these clouds cover the whole sky.

Altocumulus Lenticularis

These lens-shaped clouds form when a mountain range deflects strong winds upwards on the windward slopes and downward on the leeward slopes. This creates a giant wave or ripple several kilometres in length. Moist air enters the crests of the waves, cools as it rises and forms a cloud. When the air descends, it warms up and condensation stops. Groups of these clouds floating along in what appears to be a formation, may look like a fleet of flying saucers.

The clouds form at the top of the wave where the air cools, and disappear at the bottom of the wave where the temperatures are slightly warmer.

High Clouds

The bottoms of these clouds generally run from 5 to 12 km above the ground. These clouds are composed mostly of ice crystals.

White and orange clouds

Description

Wispy white and orange clouds, high in an evening sky over a silhouetted coastline. High clouds are composed mostly of ice crystals.

Cirrus

These thin clouds may appear as wispy streaks or streamers high in the sky. Extensive cirrus clouds may be the first sign of an approaching warm front.

Cirrocumulus

These are thin, white bands of clouds with tufted bottoms. These clouds often look like the ripples in the sand left by waves.

Cirrostratus

This whitish cloud covers the sky in a transparent veil or sheet. The cloud is usually thin enough for the sun to shine through, often producing a halo.

Cloud Movement

Clouds move in the direction that the wind at their altitude is blowing. This is why clouds may travel in one direction while the wind at the surface is blowing in another. That also explains why two types of clouds that form at different heights, such as cirrus and cumulus clouds, may blow across the sky from different directions.

For more information on clouds, visit the Sky Watchers Guide to Cloud Identification.

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2.2 Observe

Since clouds depend on water vapour condensing around particulate matter, the three are closely linked. However, there can be high humidity without much particulate matter, and high levels of particulate matter without much humidity. This can occur at ground level or high up in the atmosphere.

Measuring Humidity

Weather instruments such as a hygrometer or sling psychrometer can be used to measure humidity and relative humidity.

Hygrometer

Close-up of the needle on a hygrometer
Description

Close-up of the needle on a hygrometer. Not too many years ago, humidity was measured with a mechanical hygrometer.

Humidity is measured with an electronic hygrometer, but not too many years ago, it was measured with a mechanical hygrometer. This instrument had a long, naturally blond hair as one of the principal components. As the humidity increased, the hair absorbed moisture and stretched. This caused the indicator arm on the hygrometer to change readings. Blond hair was used because it absorbs moisture more readily than other naturally coloured hair.

Sling Psychrometer

Child holding up a sling psychrometer
Description

Child holding up a sling psychrometer. A sling psychrometer is used to determine dew point temperature and relative humidity.

A sling psychrometer is used to determine dew point temperature and relative humidity. It contains two thermometers. The bulb of one of the thermometers is covered with a wet cloth, so it is called a wet bulb thermometer. The other is called a dry bulb thermometer. The wet-bulb reading will always be equal to or less than the dry bulb because some of the heat energy is used for evaporation.

In dry air, the water evaporates quickly and causes a large drop in the wet-bulb temperature. This makes the difference in temperatures on the two thermometers greater than if the air was humid. This difference in temperatures indicates the amount of water vapour in the air.

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Observing Clouds

Cloud Cover

Cloud cover indirectly represents the amount of condensation taking place in the air. It describes the amount of sky covered by clouds from horizon to horizon.

  • Clear – No clouds in the sky.
  • A few clouds – Less than half the sky is covered with clouds.
  • Cloudy – More than half the sky is covered with clouds.
  • Overcast – All the sky is covered with clouds.

Weather Station Model

Cloud cover is one of the weather observations collected from hundreds of places and plotted on weather maps using an internationally accepted code called a station model.

The station model fits the following information into a space about the size of a dime:

  • Types of clouds present
  • Air pressure
  • Dew point
  • Cloud cover
  • Precipitation
  • Air temperature
  • Wind direction and speed

Using a Variety of Sources...How could you find out more about the different weather station model symbols for clouds and cloud cover? Do you think these symbols will continue to be used, or are they a thing of the past? Why?

Illustration showing weather at a given reporting station
Description

A symbolic illustration showing the weather occurring at a given reporting station. The information is arranged around a circle in the middle. The weather station model arranges information around a circle. Each placeholder in this diagram could be one of many possible symbols.

2.3 Predict

Canadians rely on weather reports for information that helps inform their day-to-day decisions. In summer this includes the humidex, which indicates how high the temperature feels when combined with humidity. It also includes the Air Quality Health Index (AQHI), a tool based in part on particulate matter. AQHI communicates the health risks posed by this and other air pollution.

Weather Reports: Clouds

Clouds are visible using satellite imaging, and give forecasters clues that help them track and predict local and regional weather.

Satellites

Each of ECCC’s weather centres has its own satellite receiver to pick up photos transmitted from space. Animated satellite images are available at ECCC’s weather website at, weather.gc.ca.

Weather satellites have become an indispensable tool for observing and forecasting weather because they give forecasters the ability to see the movement of entire weather systems.

ECCC uses images from two types of weather satellites: the geostationary satellite (GOES) and the polar orbit satellite (NOAA polar orbiting).

GOES

Each geostationary satellite orbits around the earth’s equator at an altitude of about 36,000 km. The geostationary satellite monitors the same portion of the earth continuously, producing a picture every 15 minutes. Because its position relative to the earth stays the same, forecasters are able to put together and animate consecutive pictures from the same satellite to show a movie of the weather. This is the view normally seen on the news.

NOAA Polar Orbiting

A polar orbit satellite travels at a much lower altitude (about 860 km above the earth) and provides more detailed images. The polar orbiter circles the earth about 14 times each day. However, as the earth rotates under it, each successive orbit covers a swath about two time zones further west.

Visible

Weather satellites use visible light cameras that take images of what you would see with your own eyes if you were on the satellite. This type of image is only transmitted during the daylight hours and cannot be used overnight.

Infrared

The second type of image is infrared (IR). The equipment senses temperatures and displays them in shades of grey--the colder the temperature of the ground or cloud top, the whiter it appears on the image. Conversely, the warmer a surface, the darker it appears. This type of picture also allows forecasters to monitor clouds overnight.

Environment and Climate Change Canada Severe Weather Bulletins

ECCC issues severe weather bulletins to keep the Canadian public advised of weather events that could affect their safety or property. These weather alerts can be special weather statements, advisories, weather watches, or weather warnings, depending on their severity.

Special weather statements and advisories are issued for events that are not severe enough to merit a warning, yet might cause general inconvenience or public concern. For example, an advisory might be issued to highlight widespread dense fog that could pose a transportation challenge, or a special weather statement might be issued to clarify a weather warning that may be in effect near our borders.

Weather watches provide a heads-up that conditions are favourable for severe weather to develop. A watch might be issued as much as 12 hours in advance, when the potential for dangerous weather has been identified, but the track and strength of the system are still uncertain. Watches may be issued for six different severe weather events to provide more advance notice of the threat.  These include a severe thunderstorm watch, a tornado watch, a winter storm watch, a snow squall watch, a tropical storm watch and a hurricane watch.

Water and ice flooding a street

Description

Water and ice flooding a street. ECCC issues severe weather bulletins to keep the Canadian public advised of weather events that could affect their safety or property.

Weather warnings are issued when severe weather is occurring or about to occur. The threshold for issuing various types of warnings will depend on the climate of an area as well as local needs. A severe thunderstorm warning is issued when a severe storm has developed, producing flooding rain, destructive winds with gusts of at least 90 km/h and/or hail at least 10 to 20 mm in diameter.

Environment Canada strives for a lead time of 6 to 18 hours, depending on the type of event. However, thunderstorms often develop rapidly, so lead times on occasion may be less than an hour. 

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Weather Reports: Humidex

The humidex is a comfort index that was invented in Canada during the 1960s. It is a measure of what high temperature and relative humidity feels like to the average person. When the relative humidity is high, perspiration does not evaporate well and it is difficult to cool down. For example, when the temperature is 32°C and the relative humidity is 75%, the air feels as if it is 46°C. 46 is the humidex reading.

Humidex And Your Comfort Level
HumidexComfort Level
20-29Comfortable
30-39Varying degrees of discomfort
40-45Almost everyone is uncomfortable
Above 45Many types of work and exercise should be restricted

ECCC displays humidex values of 25 or higher for a location with a dew point temperature above zero (0°C) and an air temperature of 20°C or more.

The highest humidex ever recorded in a Canadian city was in Windsor, Ontario, on June 20, 1953. That day, the humidex was 52 (ECCC’s climatologists worked this out using records for temperature and relative humidity).

Dew covering an autumn leaf

Description

Dew covering an autumn leaf. Dew in the morning means that there is a good chance of a bright day ahead.

 

Predict Weather Using Signs Found in Nature: Condensation and Humidity

If folks don’t want to leave it to the experts, they can look around for condensation and humidity clues to predict the weather themselves.

Dew

When dew or frost appear on the ground early in the morning, there is a good chance of a bright day ahead. That is because frost, dew or fog form more readily on clear, cool and calm nights when there are no clouds to interfere with the cooling of the ground. As calm, clear nights are typical of high pressure areas, the fair weather is likely to continue for at least another day.

Clouds

Generally speaking, the more types of clouds there are in the sky, the greater the chance of rain or snow.

Nimbostratus

These dull, gray clouds that cover the sky from horizon to horizon usually mean rain or drizzle all day.

Long white jet vapour trail crossing a clear blue sky

Description

Long white jet vapour trail crossing a clear blue sky. If you look up on a sunny day and see a jet leaving a long, white plume in a clear sky, it means the surrounding air is humid. Rain, or some other form of precipitation, may be on the way.

Cirrus

This bank of wispy clouds coming in high in the sky on a sunny day may mean a change in the weather. They are sometimes the first sign of an approaching warm front.

Towering Cumulus

When these clouds pop up rapidly on hot, humid days, it means that showers are likely. There is also a possibility that a thunderstorm will develop. If you see the sun shining behind a thundercloud, you know the cumulonimbus cloud is moving on, and the end of that particular thunderstorm is in sight.

Cirrostratus

Cirrostratus clouds can sometimes appear as halos around the sun or moon. The halo is caused by the refraction of the sun’s or moon’s rays through the clouds’ ice crystals. These clouds are an early sign that a warm front is approaching and that rain may be on the way within the next 20 to 24 hours.

Jet Trails

Airline jets sometimes leave white plumes called contrails behind them. It is the condensation trail of ice crystals left behind by the exhaust of a flying jet aircraft. These aircraft fly 8 to 12 km above the ground, pulling in very cold, dry air and spewing out hot, water-filled exhaust. The hot water vapour mixes with the colder surrounding air, and in the process, expands and then freezes in 1 or 2 seconds, forming a trail of ice crystals.

If you look up on a sunny day and see a jet leaving a long, white plume in a clear sky, it means the surrounding air is humid. Rain, or some other form of precipitation, may be on the way.

If a jet leaves no trail or only a short trail, or if the trail fades quickly, then the air at that level is relatively dry. This means the fair weather is likely to continue.

Humidity and Plants

Pine cones, tulips and daisies close when the relative humidity is high and rain may be on the way. One theory suggests that flowers do this to prevent pollen from washing away.

Exhaust filling the air over a fuel transport truck

Description

Exhaust filling the air over a fuel transport truck. You can’t always feel, see, or smell air pollution, even though it may start to affect your health.

Weather Reports: Particulate Matter

Although you can feel humidity in the air, you can’t always feel, see or smell air pollution, even though it may start to affect your health.

The Air Quality Health Index (AQHI) is a scale designed to help you understand what the quality of the air around you means to your health. It is a tool developed by health and environmental professionals to communicate the health risk posed by air pollution. The AQHI is calculated based on risks from fine and coarse particulate matter (PM2.5, PM10) as well as other common air pollutants that are known to harm human health, such as ground-level ozone and nitrogen dioxide. The index provides specific advice for people who are especially vulnerable to the effects of air pollution as well as the general public.

The AQHI communicates four primary things:

  • It measures the air quality in relation to your health on a scale from 1 to 10. The higher the number, the greater the health risk associated with the air quality. When the amount of air pollution is very high, the number will be reported as 10+. 
  • A category that describes the level of health risk associated with the index reading (e.g., Low, Moderate, High, or Very High Health Risk).
  • Health messages customized to each category for both the general population and the “at risk” population.
  • Current hourly AQHI readings and maximum forecasted values for today, tonight and tomorrow.

The AQHI is designed to give you this information along with some suggestions on how you might adjust your activity levels depending on your individual health risk from air pollution.

The AQHI is measured on a scale ranging from 1-10+. The AQHI index values are also grouped into health risk categories as shown below. These categories help you to easily and quickly identify your level of risk.

AQHI scale

Description

AQHI is measured on a scale ranging from 1--10+

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AQHI index
Health RiskAQHIHealth Messages
At Risk Population
Health Messages
General Population
Low1–3Enjoy your usual outdoor activities.Ideal air quality for outdoor activities.
Moderate4–6Consider reducing or rescheduling strenuous activities outdoor if you are experiencing symptoms.No need to modify your usual outdoor activities unless you experience symptoms such as coughing or throat irritation.
High7–10Reduce or reschedule strenuous activities outdoors. Children and the elderly should also take it easy.Consider reducing or rescheduling strenuous activities outdoors if you experience symptoms such as coughing and throat irritation.
Very HighAbove 10Avoid strenuous activities outdoors. Children and the elderly should also avoid outdoor physical exertion.Reduce or reschedule strenuous activities outdoors, especially if you experience symptoms such as coughing and throat irritation.

Illustration showing physical activities

Description

A drawing that depicts multiple physical activities that are appropriate when the Air Quality Health Index (AQHI) is low, moderate, high and very high. Always look at the AQHI health messages when choosing outdoor activities.

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2.4 Reflect

Take some time to think about how you react to a weather report. Do you look for information on weather when you make day-to-day choices? What will you do with a report about particulate matter, clouds or humidity?

What does Particulate Matter Mean to Me?

Many of the adverse health effects resulting from exposure to particulate matter are specific to the cardio-respiratory system. When we inhale particulate matter, the particles can penetrate deep into the lungs. The smaller the particle, the deeper into the lungs it can penetrate. Scientific studies have identified strong links between high levels of airborne particles and increased hospital admissions for heart and respiratory problems, as well as higher death rates from these ailments.

Depending on the length of time you are exposed, your health status, your genetic background and the concentration of pollutants, air pollution can have a negative effect on your heart and lungs. It can:

  • Make it harder to breathe;
  • Irritate your lungs and airways; and
  • Worsen chronic diseases such as heart disease, chronic bronchitis, emphysema and asthma.

Each individual reacts differently to air pollution. Children, the elderly and those with diabetes, heart or lung disease are most sensitive to the adverse health effects of air pollution.

Negative health effects increase as air pollution worsens. Small increases in air pollution over a short period of time can increase symptoms of pre-existing illness among those at risk.

For more information on the health effects of air quality, visit the Air Quality Health Index.

What Do Clouds and Humidity Mean to Me?

Clouds and humidity can send more obvious signals to you as you go about your day. Unlike particulate matter, which you may not notice without a weather report, it is hard not to detect a particularly high humidex or an overcast sky.

Pay special attention when there are clues about clouds and humidity that you can’t ignore, like thunder. Thunderstorms come hand in hand with lightning, hail and downbursts, which are serious hazards.

Thunderstorm Hazards

Lightning

Lightning kills an average of 7 people and injures 60 to 70 people each year in Canada. Lightning is also responsible for 42% of the country’s forest fires. The cost of forest fires caused by lightning has been estimated at $14 billion annually in recent years.

There is no truth to the saying that lightning never strikes the same place twice. Lightning strikes the CN Tower in Toronto about 70 times a year.

Lightning Safety Tips for Kids

You can work out how many kilometres away a thunderstorm is by counting the number of seconds between the time you see the lightning and hear the thunder and dividing the answer by 3. For example, if you count 15 seconds between the lightning flash and the crack of thunder, then the storm is about five (5) kilometres away.

Every thunderstorm produces lightning. Remember: When thunder roars, go indoors.

When thunder roars, go indoors
Description

A cartoon drawing of a cumulonimbus cloud with an angry face, and a bolt of lightning coming from the bottom of the cloud. When thunder roars, go indoors.

Indoors

  • Stay away from windows and doors.
  • Don’t use the telephone, take a shower or wash dishes. Avoid indoor swimming pools. Don’t even touch water faucets, electrical appliances or metal items that would conduct electricity.

Outdoors

  • Unsafe places include open fields, high places, tents, picnic shelters or pavilions, baseball dugouts, swimming pools and things that could conduct electricity, like metal fences.
  • If you cannot find safe shelter, make yourself as small a target as possible. Don’t lie flat. Instead, crouch down with only your toes touching the ground and lower your head.
  • Safety also means no bike riding, skateboarding or golfing until the storm has passed.
  • If you’re swimming or boating, return to shore immediately.
  • In wooded areas, go deep into a stand of trees and find a low-lying area, but never seek shelter under a solitary tree.

In a Vehicle:

  • You’re safe inside a hard-topped vehicle like a car or RV, because the outer metal body of the vehicle will divert the lightning. Keep your hands in your lap and don’t touch anything metal inside the vehicle.

Hail

Hail forms when updrafts carry water droplets into the colder reaches of a cumulonimbus cloud, where they freeze. More layers of ice are added when updrafts hurl other water droplets up and they collide with the now-frozen particles. This continues until the ice particles are too heavy for the updrafts to support and the ice particles fall to the ground as hail.

Hail Safety Tips for Kids

Indoors:

  • Follow your lightning safety plan.
  • Stay inside and away from windows that may be struck by hail.
  • Keep pets indoors.

Outdoors:

  • Find something to protect your body or at least your head.
  • Stay out of ditches or low areas that might suddenly fill with water.

In a Vehicle:

  • A car can give you reasonable protection, but be aware that extremely large hail could break windows.
  • Hail is one of the most destructive forms of severe weather in Canada. Hail stones destroy crops, kill farm animals and cause millions of dollars in damage. Fortunately, hail injures only a few Canadians each year.

Downbursts

Downbursts are another hazard of large thunderstorms. Downbursts are the downdrafts that usually accompany rain or hail. They can plunge to the ground at speeds of over 200 km/h, the speed of an EF2 tornado.

In fact, people often confuse downbursts with tornadoes, believing that only tornadoes can generate such damaging winds. Derechos (pronounced day-RAY-cho) comes from the Spanish word “straight ahead,” while tornado comes from the Spanish word for “turn.”

Derechos are long-lasting winds associated with lines or clusters of thunderstorms. They can damage an area several kilometres wide and several hundred kilometres long in a single or series of swaths of 90 km/h winds.

A microburst is a form of downburst that is less than 4 km wide. Microbursts have caused aircraft to crash and capsized sailboats.

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Section 3 Precipitation

Prior Knowledge

What do you know about precipitation and why it falls?

Snowflakes falling

Description

Large white snowflakes falling at night. Precipitation is the part of the water cycle that returns water back to Earth from clouds.

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Section Summary

Precipitation is the part of the water cycle that returns water back to earth from clouds. Clouds release precipitation when their droplets of water or ice grow big enough to fall. The type of cloud and conditions determine whether precipitation will be drizzle, rain, freezing rain, ice pellets, snow or hail.

Modern automatic weather stations and radar are used to monitor precipitation. Rain gauges and snow boards are also useful.

Canadian summers and winters both involve difficult precipitation conditions that warrant warnings. Environment and Climate Change Canada (ECCC) issues severe weather warnings such as rainfall, snowfall, freezing rain, snow squall and general winter storm warnings to help folks prepare for unseasonable and/or extreme precipitation. Weather is broadcast in many ways to ensure that everyone, no matter what technology is available to them, can access the information.  

Canadians design and plan the built environment to be ready for precipitation, sometimes even creating new inventions. When severe weather does arrive, remember to take it seriously for your health and safety.

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3.1 Read with Understanding: Precipitation

Precipitation is Part of the Water Cycle

More than 5 trillion tonnes of precipitation fall on Canada each year. About 3 trillion eventually runs into lakes and rivers. The other 2 trillion evaporates from the earth’s surface or passes back through plants through the process known as transpiration.

The Pacific Ocean, Gulf of Mexico and Caribbean Sea are the primary sources of water for precipitation in Canada, but water also recycles itself several times between the air and the ground. The water evaporates from soil, lakes, and rivers, rises into the air as water vapour, forms clouds, and then falls elsewhere as rain, drizzle, freezing rain, snow or hail.

Collaboration, collecting data, technology... Ask students to make a list of all the different sounds they hear from precipitation, such as the sound of cars on wet pavement or rain on the roof. Record these and use the sounds to create a guessing game either in-person or online.

Rain droplets on a window pane

Description

Rain droplets of various sizes covering a window pane. Precipitation is called rain when the water droplets are greater than 0.5mm in diameter.

First Clouds, Then Precipitation

Rain, snow, hail, and other forms of precipitation occur when water droplets or ice crystals grow until they are too heavy for the air currents in a cloud to support. One million tiny water droplets are needed to form an average rain drop, about 1mm in diameter. It takes more than 30 minutes for a raindrop to grow.

Drizzle: Precipitation is called drizzle when the water droplets are less than 0.5 mm in diameter, which is about the size of the head of a pin. Drops of drizzle fall at a rate of 1 to 2 m/s while raindrops reach speeds of 4 to 9 m/s.

Rain: Precipitation is called rain when the water droplets are greater than 0.5 mm in diameter. Some raindrops are as large as 10 mm across.

Art: Comparing Raindrops

Materials

  • dark sheets of construction paper OR white paper and watercolour paints
  • a rainy day

Instructions

  1. Paint the plain white paper with watercolours and let dry.
  2. On a rainy day, go outside and hold the dark construction paper or painted paper in the rain parallel to the ground.
  3. Count to 10.
  4. Return to the classroom and observe the raindrops on the paper.

Why it Works

Raindrops leave marks of various sizes on the paper because it dissolves, dilutes and splatters the watercolour pigments. Raindrops are different sizes, some as small as 1mm, others as large as 10 mm.

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Types of precipitation

Different types of clouds and conditions produce different precipitation. Precipitation comes in three forms: liquid, freezing and frozen. Precipitation may be small and fall as drizzle or light snow, or clouds may form larger droplets and release steady rain or snow. Other clouds have convective air currents in them, so they release rain in bursts or showers.

In the winter there can be as many as four different types of precipitation when a warm front passes: rain, freezing rain, ice pellets and snow.

Freezing Rain

The classic recipe for freezing rain is a layer of warm air hovering above a shallow layer of cold air. Raindrops fall from clouds in the warm layer of air, then pass through the cold layer where temperatures hover around freezing.

Here, raindrops cool to the freezing point or just below it, becoming super-cooled. These very cold raindrops freeze on contact when they hit a colder object such as an overhead electrical wire or the branch of a tree. This creates glaze ice.

Ice Pellets

Ice pellets form under the same conditions as freezing rain. The water droplets form in the higher, warmer layer of air and fall into the lower layer of colder air. In this case, though, the cold layer is deep enough to give the water droplets time to freeze before they hit the ground.

Drawing showing precipitation

Description

A drawing that shows precipitation falling from clouds influenced by both warm air and cold air. The precipitation types shown are rain, freezing rain, ice pellets and snow. In the winter, there can be as many as four different types of precipitation when a warm front passes.

Snow

Snow is precipitation of white or translucent ice crystals that are clustered together to form snow flakes. The shapes and sizes of snowflakes depend on the temperature and humidity in the cloud, and in the air below it.

Big, soggy flakes are conglomerations of hundreds of smaller snowflakes that have fallen through relatively mild air and stuck together. Some of these flakes have measured as much as 2 cm across. In contrast, dry snow tends to fall as small, single flakes that do not bind together as they fall through cold, dry air.

About 36% of Canada’s precipitation falls as snow, compared to the world average of 5%.

Sparkles on snow

Description

Sparkles on a layer of freshly fallen snow. About 36% of Canada’s precipitation falls as snow.

Hail

Hail forms only in cumulonimbus clouds when strong updrafts carry water droplets high into the upper reaches of the clouds. Here the water droplets freeze, even in summer. Layers of ice are added when the updrafts throw more water droplets upward, which then collide with the frozen particles. This process continues until the ice particles become too heavy for the updrafts to support. Then the ice particles fall as hail.

A hailstone of a few millimetres in diameter needs updrafts of more than 100 km/h to support it. In Canada, hailstones range in size from 5 mm (the size of a pea) to 114 mm (the size of a grapefruit).

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3.2 Observe

Measuring Precipitation

Modern automatic weather stations use remote-sensing technology to measure current conditions.

The precipitation sensor measures the speed at which precipitation particles are falling. This, combined with air temperature, identifies the type of precipitation because droplets of different size and composition fall at different rates.

To measure the depth of snow, a high-frequency pulse of sound is reflected off the ground, indicating how far it is to the snow’s surface. Similarly, the reflection of a laser beam from a cloud determines its height.

Some stations are also equipped with video cameras so forecasters can see a digital picture of the weather at that location.

Radar

Meteorologists use conventional radars to determine the size, motion, and concentration of precipitation in clouds within a 200 to 400 km range. The radar transmits a burst of microwave energy. If there are water droplets, some of the microwaves are reflected back and are detected by the antenna. The greater the size or density of water droplets, the more microwave energy that returns.

Doppler Radars

ECCC has a Doppler weather radar network that covers areas of the country that are prone to severe weather. About 90% of the country’s population lives in these areas. 

Doppler radar measures the intensity, speed and direction of precipitation within a 250 km range. This helps forecasters to identify early signs of severe weather, such as when clouds are starting to rotate into a funnel cloud, and could possibly become a tornado.

Rain Gauge

A rain gauge is a weather instrument used to measure the amount of rain that has fallen. To set one up, attach it to a post so that the rain gauge is level. Ensure that the gauge’s top extends above the post and that the post is located away from buildings, trees or any other structures.

To take a reading, look at the level of water in the rain gauge and record the amount in millimetres. Empty the gauge and dry it thoroughly with a clean cloth after every reading. 

Building a Weather Instrument: Recycled Rain Gauge

Materials

  • a plastic 2 L pop bottle with straight sides
  • ruler at least 15 cm in length
  • scissors
  • stones or large gravel
  • clear tape
  • water

Instructions

  1. Cut the bottle about 10 cm from its top. Save the top part.
  2. Place stones or gravel in the bottom of the bottle until they fill the bumps in the bottom and come up to the part of the bottle where the sides are straight. This will add weight to the gauge to make it more stable.
  3. Tape the ruler to the side of the bottle so that the zero mark on the ruler is a centimetre or two above the stones.
  4. Pour enough water into the bottle so that the water level is at the zero mark on the ruler.
  5. Take the top of the bottle (the part you cut off earlier), turn it upside down, and put it into the bottom portion so that it looks like a funnel.
  6. Set your gauge in an open area away from trees or buildings that may affect the amount of rain that falls into the bottle.
  7. When it has rained, take a reading using the ruler taped to the side of the bottle. Then pour out the excess water until the water level is once again at zero. (If you pour out too much water, simply add more until the water level reaches zero on the ruler.)

Why it Works

The rain gauge collects rain as it falls. This works as long as it is in an open area and it starts exactly at zero. Water will evaporate if you leave your rain gauge out in the sun, so check that the water level is at zero before each use.

Measuring Snow

Find a patch of undisturbed snow on flat open ground away from any trees or overhanging roofs. Try to avoid areas where the snow has drifted into piles or the wind has blown the fresh snow away.

Measure the depth of the snow in centimetres using a long ruler or a metre stick. Keeping the ruler straight, push it into the snow until the ruler hits the ground below. Do this several times in different spots, then calculate the average.

Ten centimetres of snow is approximately equal to 10 mm of rain, depending on whether the snow is wet or dry. If you have had both rain and snow on the same day, measure the total amount of liquid in the rain gauge in millimetres.

There are three ways to determine how much snow fell since your last observation.

Snow Board

Use a board that is about 40 cm long and 40 cm wide. It must be light enough to sit on top of the snow but heavy enough to stay in place on windy days. Push the board into the snow until the top is level with the snow’s surface. If the forecast calls for a heavy snowfall, mark the board’s location with a flag or stick so you can find it the next day. Measure the amount of snow on the board, clean it off and place it back in the snow.

Frozen pine branches

Description

Frozen pine branches dripping with drops of rain. If you have had both rain and snow on the same day, measure the total amount of liquid in the rain gauge in millimetres.

Footprint in snow

Description

Footprint in freshly fallen snow. Snow may compact, sublimate, or melt between measurements.

Clean Slate

After measuring the amount of snow that has fallen, shovel and sweep the area clean so it is clear for the next snowfall.

Difference

Measure the depth of all snow on the ground after each snowfall. The latest snowfall amount is the different between the current depth and the previous depth. It is not exact because snow may compact, sublimate or melt between measurements.

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3.3 Predict

Weather Reports: Precipitation

Chance of Precipitation

The chance of precipitation is the likelihood that measurable precipitation (0.2 mm of rain or 0.2 cm of snow) will fall on any point of the forecast region during the forecast period.

A 30% chance of precipitation means that there is a 3 in 10 chance of precipitation in the area. In other words, there is a 30% chance that rain or snow will fall on the area and, therefore, a 70% chance that it won’t.

A low chance of precipitation does not mean a sunny day; it only means a day where the chance of rain or snow is low.

Precipitation Weather Warnings

ECCC issues a variety of severe weather warnings specifically related to precipitation.

Ice on a branch
Description

Thick ice accumulation on a tree branch. Freezing rain can accumulate on trees and overhead wires.

Rainfall Warning

  • Issued when heavy or prolonged rainfall is sufficient to cause local or widespread flooding or flash floods. 

Snowfall Warning

  • Issued when an unusually high amount of snow is expected to fall in a comparatively short period of time. In Vancouver, 5 cm of snow in 12 hours would be unusual, whereas in Ontario, a warning is only issued if 15 cm is expected in that length of time.

Freezing Rain Warning

  • Issued when freezing rain is expected to last long enough for the accumulation to create hazardous walking and driving conditions or damage to trees and overhead wires.

Snow Squall Warning

  • Issued for localized, limited duration, intense snowfall that reduces visibility significantly and may be accompanied by strong, gusty winds.

Winter Storm Warning

  • A broader warning issued by ECCC in some regions because of serious combinations of different winter weather phenomena. 

Getting the Message Out

ECCC uses a variety of delivery methods to ensure that everyone, no matter what technology is available to them, can access weather information.  

Weatheradio

ECCC has its own radio network, broadcasting continuous weather information 24 hours a day. Known as Weatheradio, this network uses VHF frequencies so that specially equipped receivers will automatically activate when warnings are issued for your area. To learn more about Weatheradio and find the transmitter location closest to you visit ECCC’s website.   

Internet

Millions of people visit ECCC’s main weather Web site at weather.gc.ca to look at radar imagery or to check the forecast for any of the hundreds of towns available on drop-down menus.

Media

The most popular source of weather information for Canadians is still their local media outlet-- radio, television or newspaper--and ECCC feeds weather information to them directly through wire services and a special website just for media.

Listening to Folklore

Most weather lore is fanciful, but some actually do make sense, linking weather indicators to upcoming weather.

Showers Before Seven, Fine Before Eleven

Showers in the morning usually do not last long--for good reason. If they formed during the night when it was cool, then when the sun comes up and heats up the day, the humidity drops, the clouds dry out and the rain ends.

Collaboration and Community...What weather lore or folk sayings can you collect from your community or family members? Are they good predictors of the weather?

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3.4 Reflect

What Does Precipitation Mean to Me?

Precipitation and the Built Environment

Precipitation affects how we design and plan our built environment. For example, contractors build adequate support for the maximum anticipated snow load expected in a region. This can prevent a roof from collapsing.

When severe weather events happen, it is not only the large-scale events that affect the economy, but even small ones. A sudden thunderstorm has a large impact to the farmer who recently cut hay or the contractor who poured $10,000 worth of concrete.

The Canadian economy absorbs not only the direct costs for property damage from bad weather, but also millions of dollars worth of indirect costs from reduced sales and cancelled events.

Invention

Canada’s weather, specifically winter, has brought out the best in some of the country’s more inventive minds. Canadians invented the snow blower, the snowmobile, and snow garments such as polar fleece. Not surprisingly, Canadians also invented insulation and frozen fish, and have perfected the art of making ice wine.

Using a Variety of Sources, Collaboration...Have your students list ten occupations greatly affected by the weather and identify which weather element is the most critical for each. Then, see if they can identify two occupations not affected in any way. Remind them that most jobs are dependent to some degree on travel conditions to get to work and the availability of electricity once they arrive.

Severe Weather

When severe weather does arrive, remember to take it seriously for your health and safety. For example, freezing rain is a significant winter hazard in Canada, but can also occur in late fall or early spring. Freezing rain glazes trees, hydro lines, roads and sidewalks with ice. Buildups of ice can bring down branches and trees as well as overhead power and telephone lines. This can disrupt power supplies and communications for days. Even a small accumulation of ice may pose a risk to both pedestrians and drivers.  

Ice storm is a term used to identify particularly severe freezing rain events. Most ice storms last a few hours, but some continue for up to three days. The ice storm that hit New Brunswick, Quebec and eastern Ontario in January of 1998 went on for six long days. The storm was directly or indirectly responsible for the deaths of 25 people. At its height, the storm left nearly three million people in Quebec and Ontario without electricity or heat. A week after the storm ended, nearly one million people were still without light or heat.

Winter Storm Safety Tips for Kids

  • Stay indoors and wait out the storm.
  • If you must go outside for a short period, dress in multiple layers of loose-fitting clothing.
  • Outer clothing should be hooded, tightly woven and water repellent.
  • Mittens are warmer than gloves.
  • Wear a hat, because most body heat is lost through the head.
  • If it is very cold, cover your mouth with a scarf to protect your lungs from the cold air.
  • Never touch a power line that may have come down due to wind or ice buildup. It may still be “live” and you could be electrocuted.

If you become stranded while traveling in a vehicle, wait for rescue:

  • Stay in the car -- you won’t get lost and the car will provide shelter.
  • Turn the car off. Ensure that the exterior exhaust of your car is clear of snow so you don't get carbon monoxide poisoning in the car.
  • Keep your seatbelt on and put on your hazard lights. Even if you are pulled over, people can still hit you.
    Keep dry and warm. If you begin to sweat, remove your hat or one layer of clothing.
  • Keep fresh air in the car by opening the window 1 cm or less on the side away from the wind.
  • Exercise your arms and legs periodically to keep your hands and feet warm.
  • Keep watch for traffic or for search parties.

Precipitation as Inspiration

Precipitation is often used in song, stories and art to create a mood.

Using a Variety of Sources, Collaboration...Collect children’s storybooks showing different precipitation and share them with others. Ask family members for a story or memory of an event involving precipitation.

Technology...Record 5 to 30 second clips of movies that use precipitation to create a mood. Use movie editing software to organize and weave the clips together, labeling them with scientific facts.

Snow on a duck

Description

Snow covering the bill of a mallard duck. Precipitation is often used in songs, stories and art to create a mood.

Rainbow

Description

Rainbow in the sky over fall foliage. When a rainbow forms, the water bends light into its component colours.

Demonstration: Make a Rainbow

Materials

  • clear plain glass bowl with water in it
  • sunlight or a full spectrum flashlight
  • small flat mirror
  • heavy white paper/cardstock

Method

  1. Place the bowl of water on a desk or table near a blank wall or heavy white paper.
  2. Put the mirror in the water so that the mirror rests against the side of the bowl at a 45° angle.
  3. Standing behind the mirror, shine the flashlight straight down on the mirror.
  4. If using natural sunlight, angle the mirror until you see a rainbow.

Question

  • Although there is water and sunlight in the sky, there are no mirrors. How does a raindrop do this?

Explanation

Light bends in water. Even though light looks white, it is actually made up of different colours. When the rainbow forms, the water bends the light into its component colours and the mirror reflects those colours back out of the water. This is also what happens to sunlight. It, too, is bent, revealing its colours when it enters the front of a raindrop. Then, if the angle is right, it is reflected by the back of the raindrop.

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Section 4 Wind

Prior Knowledge

What do you know about wind, the pollution it carries, air masses, and what happens when they meet?

Seagulls

Description

Seagulls flying on wind currents along the shore. When a current of air warms up and rises, new cool air rushes in to fill the space.

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Section Summary

Think for a moment about birds. There are birds all over the earth. As you know, many kinds of bird migrate huge distances across the earth, picking up travellers as they go.

Then, even though they move along, there is movement within the flocks. The birds twist and turn, each landing on its own twig or branch. When one takes off, another rises up to fill the space. They fly up, down and side to side. They are fluid.

There are also different kinds of birds, different species, each originating in its own region, each with its own movements.

And so it is with air. Air moves huge distances across the earth. These global winds set up the main direction for air currents in an area--they are prevailing, urging others to come along.

Yet, even though air moves along in a certain direction, there is movement within it. Local air currents twist and turn, each brushing by its own twig or branch. When a current of air warms up and rises, new, cool air rushes in to fill the space. Currents move up, down and side to side. They are fluid.

There are also different kinds of air masses, each originating in its own region, each with its own features. With the right tools, meteorologists can watch these large air masses move around.

Also, air masses essentially run into each other at fronts. Imagine the chaos if two flocks of birds were headed toward each other from different directions. Would one quickly fly up and the other go down? Would they spread apart and swirl around in confusion? Would one retreat? With air, this interaction of air currents causes dramatic and sometimes violent weather.

No, air is not alive, but it certainly affects our lives. Air can be healthy and clean or polluted. Polluted air can travel and cause problems in other regions. The atmosphere is an extremely complex, dynamic three-dimensional system.

Consider this... Although air is not alive, we often attribute it with human or animal qualities, characteristics, or motives. Collect some examples of this from books and poems or come up with some on your own.

Who Has Seen the Wind?
By Christina Rossetti

Who has seen the wind?
Neither I nor you:
But when the leaves hang trembling,
The wind is passing through.
Who has seen the wind?
Neither you nor I:
But when the trees bow down their heads,
The wind is passing by.

Source: The Golden Book of Poetry (1947)

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4.1 Read with Understanding: Wind

Air Pressure

Air expands and rises when heated. This happens because air molecules bounce around and move apart as they warm up. Since the air is rising, it doesn’t put as much pressure on the earth’s surface, so there is a low pressure area underneath the warm, rising air. As soon as the warm air begins to rise, cooler air flows in to replace it. This flowing air is wind.

Cold air sinks naturally because its molecules are close together, making a high pressure area. Air always flows from high pressure areas to low pressure areas. The greater the difference in air pressure between the two areas, the stronger the winds.

Global Winds

Air moves huge distances across the earth because warm air rises at the equator and cool air from the poles rushes in to replace it. Then, the rising warm air fans out towards the north and south poles where it cools, sinks, and moves back toward the equator.

This movement of air from the poles to the equator would go straight up and down if the earth did not rotate. But because the earth spins, the winds swerve. This is called the Coriolis effect. In the Northern Hemisphere, this effect makes the wind swerve to the right, and in the Southern Hemisphere, the wind swerves to the left.

Global winds are also responsible for carrying air pollution around the earth. Air pollution generated in one place is transported long distances by global wind, from hundreds to a few thousand kilometres in a single day. During this travel, pollutants can be deposited on the ground or on buildings, and can undergo chemical changes. These chemical changes can form an entirely different pollutant. For example, volatile organic compounds and nitrogen oxides may react with oxygen and energy from the sun to form ground-level ozone.

Global winds set up the main direction for air currents in an area. They are prevailing winds. In Canada, the prevailing winds blow from west to east and are called Westerlies. However, North America may owe its discovery to a different prevailing wind: Trade Winds. These carried Christopher Columbus across the Atlantic Ocean in 1492.

Local Winds

Even though air moves along in a certain direction, there is movement within it. Local air currents twist and turn. When a current of air warms up and rises, new, cool air rushes in to fill the space. Currents move up, down and side to side. They are fluid.

In Canada, wind speed is given in kilometres per hour (km/h), and it is named for the direction from which it blows. Ask the wind where it is from, and it will tell you. A north wind comes from the north.

Waves

Description

Sea breeze creating waves and blowing grass along a Canadian coastline. Winds blowing on shore are called sea breezes or lake breezes.

Land and Sea

The direction and strength of the winds are affected by local differences in air pressure and temperature, as well as lakes, hills and valleys.

Water

The Atlantic and Pacific oceans, as well as large lakes such as the Great Lakes, cause local land breezes and sea (or lake) breezes.

This happens because land heats and cools more quickly than water. On a warm, sunny day the air above the land warms, expands, and rises. Cooler air from a nearby ocean or lake blows in to replace the rising air. The rising air travels out over the water, where it cools and sinks to replace the cooler air blowing on shore. In this cycle, the winds blowing on shore are called sea breezes or lake breezes.

In the evening when the sun has gone down, the cycle reverses itself. Since land also cools more quickly than water, the air over the water is now warmer than the air over the land. The air heated by the water rises and is replaced by cool air from the land. At the same time, the warm air from the water moves over the land, where it cools and sinks. In this cycle, the winds blowing off shore are called land breezes.

Sea breeze and land breeze

Description

A drawing using arrows that depict the movement of air over sea and land that occurs when there is a sea breeze versus a land breeze. Sea breezes and land breezes occur because land heats and cools more quickly than water.

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A similar process occurs between hills and valleys, where the valleys are normally cooler than the hills during the day. Cities and natural features of the landscape such as forests also affect winds.

This is particularly important when local winds carry air pollution. For example, several cities, including the Greater Vancouver Region, lie within the Fraser Valley, where sea breezes push air toward mountain walls. In certain temperature conditions, this traps air that is often polluted by automobile exhaust and other sources. This air is trapped at ground level, where people and animals breathe it in.

Map of North America

Description

A map of North America that has blue arrows overlaid to depict the movement of cold air masses from the north, and red arrows to depict the movement of warm air masses from the south. Air masses are pockets of air with similar temperature and humidity.

Air Masses

There are also different kinds of air masses, each originating in its own region, each with its own features. Air masses are pockets of air with similar temperature and humidity. They extend for hundreds of kilometres and are often classified according to the region that produced them.

For example, an air mass may be called an Arctic air mass if it is cold, dry air that was over snow and ice for a few months in the Arctic. A tropical air mass might be one that becomes warm and moist sitting above the Gulf of Mexico or the Caribbean Sea.

These air masses move, picking up or releasing moisture and heat as they go. For example, an air mass travelling from the Arctic may warm and gain moisture if it moves over one of the Great Lakes. Another air mass may dry out as it moves inland from the Pacific Ocean, losing its moisture in the form of rain or snow as it rises and crosses over the Rocky Mountains.

Cold front

Description

A drawing that depicts the gentle slope of warm air rising during a warm front versus the steep slope of air quickly rising during a cold front. A cold front pushes warm air out. A warm front is the edge of warm air that arrives when cold air retreats.

Fronts

Air masses essentially run into each other at fronts. A front is the boundary between an air mass that is entering a region and one that is leaving. Usually the two air masses have different origins with very different temperatures and humidities.

Cold air masses influence the weather by moving forward or retreating out of an area. A warm air mass will never push a cold air mass out of a region because cold air is heavier and denser.

Demonstration: A Cold Front has a Steep Slope

Method

  1. Rest your hands flat on your desks with your palms down.
  2. Slide your hands forward toward the front edge of the desk, pause, and pull them backward to the original position.

Questions

  • What happened to your fingers as you pushed your hands forward? Was there a difference when you pulled your hands back?

Explanation

Your fingers probably buckled when you pushed your hands forward, as advancing air does, and then flattened when they were drawn back. This is similar to retreating air. The slope of a cold front is, on average, four times steeper than the slope of a warm front. When a cold air mass pushes into an area, there is surface friction between the advancing air and the land beneath it. This friction causes the leading edge to buckle.

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Fronts May Cause Severe Weather

The interaction of cold and warm air causes dramatic and sometimes violent weather. Cumulonimbus clouds often develop along a cold front where warm, humid air is rapidly forced up. This can result in thunderstorms and even tornadoes.

Tornadoes

Tornadoes begin as funnel clouds, violently rotating columns of air extending from the base of a thunderstorm. Some funnel clouds never quite reach the ground, disappearing back into the parent cloud. If a funnel cloud does touch the ground, then it is a tornado.

The bottom end of a tornado can range in width from approximately 2 m to 2 km. For instance, the tornado that ploughed through Edmonton on July 31, 1987 was about 1 km wide.

Tornadoes rarely travel in a straight line. They cut an erratic course, often bouncing from spot to spot. However, they generally move from the southwest to the northeast at a speed between 20 to 80 km/h.

On average, most tornadoes last about 5 to 10 minutes and travel for about 6 km. However, the Edmonton tornado cut a swath through Alberta’s capital nearly 40 km long. The tornado that raced through Grand Valley in southern Ontario, on May 31, 1985, travelled for 110 km before dissipating.

Demonstration: Simulating a Tornado

Materials

  • two 2 L clear plastic soft drink bottles
  • water
  • food colouring (optional)
  • duct tape
  • scissors
  • pencil
  • ruler
  • cloth or paper towels

Method

  1. Fill one of the bottles with water until it is half full. Add a few drops of food colouring to make the water more visible.
  2. Cut a 5 cm piece of duct tape and cover the mouth of the bottle containing the water.
  3. With the pencil, make a hole in the centre of the duct tape. Make sure that the hole is a little bigger than the pencil.
  4. Take the second bottle and turn it upside down on top of the bottle containing the water, so that the mouths of the bottles line up. With the cloth or paper towel, wipe any moisture from the necks of the two bottles.
  5. Cut more duct tape and wrap it around the necks of the bottles so they are firmly attached.
  6. Hold the two bottles by the neck. Invert them so that the bottle containing the water is on top, and immediately start spinning them in circles.
  7. Put the bottles on the table with the empty one on the bottom.

Questions

  • Why does this look like a tornado?
  • What part of the tornado do you expect to be the most dangerous?
  • Why do you think the origin of a tornado is called a funnel cloud?

Explanation

Tornadoes are fast, violent swirling winds. In this demonstration, the spinning of the bottles and funnel-shaped opening causes the water to take the shape of a tornado. The hole in the bottle allows for the appearance of the tornado’s tail--the most dangerous part of the tornado.

Tropical Storms and Hurricanes

Peak Atlantic hurricane season is between August and October, when the ocean surface is at its warmest. Warm water, rapid cooling, wind, and the Coriolis effect are conditions that combine to form a hurricane.

Warm Water

  • Hurricanes form over warm, tropical ocean water where it is at least 26.5°C. 

Rapid Cooling

  • The atmosphere above the ocean must cool off rapidly with height, so that rising warm air will continue to rise through the cooler layers, allowing the disturbance to grow.

Wind

  • Winds at all levels of the atmosphere from the ocean right up to 9000 m must be blowing in the same direction, and about the same speed.

Coriolis Effect

  • This is what makes the winds spiral. A hurricane seldom forms any closer than 500 km to the equator because of this effect. Refer to the section on Global Winds on page 4-4 to learn more about the coriolis effect.

Hurricanes Develop in Three Stages

Tropical Depression

A large area of thunderstorms persists for more than one day, and the circulation of air is organized enough to produce sustained winds of between 37 and 62 km/h.  

Tropical Storm

The low pressure centre deepens, with strong thunderstorms and a well defined circulation pattern produces sustained winds reaching 63 km/h or more. Tropical storms are identified by giving them a name to reduce confusion when more than one storm is active.

Hurricane

Circulation intensifies and wind speeds increase to 119 km/h or more. At this stage, an “eye” or calm area forms in the innermost part of the storm. Spiral bands of torrential rain rotate around the “eye” of the hurricane.

Blizzard

Description

Century farmhouse obscured by blowing snow. Canadian literature abounds with true stories of pioneers, farmers, ranchers and explorers who froze to death only metres away from shelters they could not see.

Blizzard

Blizzards combine high winds, bitter cold and blowing snow. They are dangerous on several counts. First, the snow is often powdery and fine enough for you to breathe into your lungs. Second, the combination of bitter cold and high winds can cause frostbite within seconds. Third, the blowing snow and high winds often reduce visibility to almost zero.

Canadian literature abounds with true stories of pioneers, farmers, ranchers and explorers who froze to death only metres away from the shelter they could not see. In Canada, blizzards are most common in the southern Prairies, the Maritimes and the eastern Arctic.

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4.2 Observe

With the right tools, meteorologists can watch air masses move around and measure the speed and direction of local winds. Air pressure measurements help when predicting wind, since air always blows from areas of high air pressure to low air pressure.

Measuring Air Pressure

Barometer

The barometer measures air pressure, or the weight of a column of air above a given spot. Before you use a barometer for the first time, set it to the mean sea level (MSL) pressure for your area. You only have to do this once.

Environment Canada gives air pressure readings in kilopascals. Most barometers, however, measure the air pressure in inches and millibars. To convert kilopascals to millibars, multiply the number in kilopascals by 10. To convert kilopascals to inches, divide the number in kilopascals by 3.386.

Barometer

Description

Close-up of a barometer. If the gold needle is no longer lined up with the black needle, you know that the air pressure has risen or fallen since you last set it.

As soon as you have the mean sea level reading in the correct units for your barometer, immediately set the barometer. Turn it over and adjust the small set screw until the black needle at the front is over the current air pressure. The black needle will move whenever the air pressure changes.

Now turn the gold knob on the front of the barometer until the gold needle is over the black needle. The gold needle acts as a reference and will stay put unless you move it. The difference between the two tells you if the air pressure has risen or fallen since you last set it.

Hang the barometer at eye level on a wall indoors away from direct sunlight, heat or air conditioners. Sunlight and sudden blasts of hot or cold air may affect the readings.

Do not take the barometer off the wall to read it. First, tap it gently. Wait for a minute or so and take the reading. Reset the gold needle by moving it over the black needle.

Generally speaking, when the air pressure rises, it means fair weather is approaching, and when the air pressure falls, it means unsettled weather is approaching. Focus on the numeric readings for the day and the trends that you see over time.

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Building a Weather Instrument: Barometer

Materials

  • empty glass container or soup can
  • elastic band
  • glue
  • adhesive tape
  • large balloon
  • drinking straw
  • index card about 8 cm by 13 cm

Instructions

  1. Cut a piece out of the balloon large enough to cover the top of the glass jar or soup can.
  2. Stretch that piece of the balloon tightly over the top of the jar or can and secure it tightly in place with the elastic band.
  3. Cut the straw so that it is about 10 cm long and trim one end to a point.
  4. With the sharpened end pointing out, lay the straw on the balloon with the flat end at about the centre of the balloon.
  5. Glue the straw in place.
  6. Draw reference marks on one of the long edges of the card at roughly 5 mm intervals. Tape the opposite (unmarked) side of the card to the jar, with the narrow end of the rectangular card extending above the jar top and the marked edge just behind the straw. The marked edge should stick out so that the sharpened end of the straw points to the reference marks.
  7. Chart the position of the straw against the reference marks on the card each day. This does not give you a numeric reading, but it tells you whether the air pressure is rising or falling. The pressure trend is an important tool in forecasting.

Why it Works

The stretched piece of the balloon acts as a membrane. When the air pressure outside the jar rises, it pushes down on the balloon, forcing it slightly into the jar. This, in turn, causes the end of the straw to rise. Similarly, when the air pressure outside falls, the air pressure in the jar is greater than the air pressure around it, forcing the balloon to bulge slightly. This causes the end of the straw to drop.

Keep your barometer away from sources of heat such as radiators and sunny window ledges. If it is close to a source of heat, then your barometer will act more as a thermometer, with the air inside expanding and contracting to reflect changes in temperature, not pressure.

Wind vane

Description

Wind vane on the top of a metal roof. Wind direction can be determined using a wind streamer or a compass.

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Measuring Wind Direction

Wind direction indicates the origin of the wind. For example, a north wind blows in from the north. Wind direction can be determined using a wind streamer or a compass.

Compass

Use a compass to find north. Then, select a landmark such as a hill, building or lake to identify one of the four points on the compass--north, south, east or west. This is your point of reference. To figure out wind direction, compare the movement of the flags or tree branches with your point of reference.

Wind Streamer

Find an area outside, such as a hill or a playing field, where there are no buildings or trees to interfere with the wind. Attach four streamers to the north, south, east and west positions on a paper plate. Mark the positions. Hold the plate in front of you so that it is parallel with the ground. Turn the plate so that the north on your wind streamer is facing north. You can find north the first time using a compass.

Watch to see which direction the wind blows the streamers. If the streamers are blowing toward the south, then the wind is coming from the north. It is a north wind.

Measuring Wind Speed

Beaufort Scale

On days when winds are light, you may want to use the Beaufort Scale to estimate wind speed. British Rear Admiral Sir Francis Beaufort invented this scale in 1805 as a way of estimating the speed of winds at sea. The scale was later modified so that it could be used on land.

OBSERVATIONWINDSSPEED (km/h)BEAUFORT
Smoke rises straight upCalmLess than 10
Smoke drifts, but weather vanes do not turnLight air1 to 51
Leaves rustle, weather vanes move, you feel a light breezeLight breeze6 to 112
Wind extends a little flag, keeps leaves and small twigs in motionGentle breeze12 to 193
Wind raises dust, loose paper and small branches kept in motionModerate breeze20 to 284
Wind sways small trees and small waves form on pondsFresh breeze29 to 385
Large branches of trees move, telephone wires whistle and it is hard to use an umbrellaStrong breeze39 to 496
Trees bend and walking against the wind is hardNear gale50 to 617
Twigs break off treesGale62 to 748
Houses and roofs are damagedStrong gale75 to 889
Trees are uprootedStorm89 to 10210
Damage is widespreadViolent storm103 to 11711
Tremendous damage and loss of lifeHurricaneAbove 11712
Child measuring wind speed
Description

Child measuring wind speed with an anemometer. A wind gauge, or anemometer, measures the force or speed of the wind.

Wind Gauge

A wind gauge, or anemometer, measures the speed of the wind. ECCC records wind speed in kilometers per hour (km/h).

To use a wind gauge, stand in an open spot away from any buildings, hills, walls or trees that may block the wind or change its direction and speed. Find out the general direction of the wind by looking at tree branches or flags. Hold the wind gauge up into the wind so that the dial is facing you. Watch the speed on the dial. Slowly turn the gauge a little to the left and then to the right, watching to see where the wind speed is the greatest. Make a note of that measurement.

Blowing in the Wind

Description

Lone tree bent over and blowing in the wind. Find out the general direction of the wind by looking at tree branches or flags.

 

Building a Weather Instrument: Anemometer

Materials

  • heavy needle, sticky putty, or hot glue
  • thread
  • ping pong ball
  • protractor
  • tape

Instructions

  1. Cut a piece of thread about 20 cm long.
  2. Thread the needle and tie a large knot in the end of the thread. Then, stick the needle into one side of the ping pong ball and pull it out the opposite side. Alternatively, use sticky putty or hot glue to attach the thread to the ping pong ball.
  3. Tie or tape the thread to the centre of the straight base of the protractor so that the ball hangs below the part of the protractor marked with angles. If the protractor is held level, where there is no wind, then the ball will hold the thread over the 90° mark.
  4. Take the protractor outside. Hold it level and parallel to the wind. The wind will blow the ball. When it does, note the position of the thread on the protractor.
  5. Record the angle and use the chart to convert the angle to a wind speed.
Angle of Thread on ProtractorKilometres per hour
90°0
85°9
80°13
75°16
70°19
65°22
60°24
55°26
50°29
45°32
40°34
35°38
30°42
25°46
20°52

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4.3 Predict

Long grass

Description

Long grass blowing in the wind. Wind is included in a forecast when it is expected to be at least 20 km/h.

Wind is reported in a number of ways because there are a lot of different weather conditions that are exacerbated by wind. Wind can make a cold day dangerously cold. It can blow snow or dust, reducing visibility. Tornadoes and hurricanes can bring winds that devastate whole communities.

Weather Reports: The Wind Chill Index and Extreme Cold Warnings

Wind chill is an expression of the cooling sensation you feel on your skin when wind is combined with low temperatures. Wind chill uses temperature-like units to represent the feeling of cold on your skin. It compares the wind’s effect to the way your skin would feel on a calm day with that temperature. For example, if the outside temperature is -10°C and the wind chill is -20, your face will feel as cold as it would on a calm day when the temperature is -20°C.

Frostbite becomes a risk when wind chill reaches -27. The coldest wind chill in Canada occurred at Kugaaruk in Nunavut. The temperature outside was -51°C and the winds were 56 km/h, producing a wind chill of -78.

The wind chill index can help you plan your outdoor activities and decide what to wear.

Weather Reports: Severe Weather and Wind Warnings

ECCC issues a variety of Severe Weather Warnings specifically related to wind.

Wind Warning

  • Issued for sustained winds of at least 70 km/h or gusts of at least 90 km/h or higher.

Extreme Cold Warning

  • Issued when winds of at least 15 km/h are expected to combine with very cold temperatures and wind chill values to produce hazardous outdoor conditions lasting more than three hours. The criteria for this type of warning vary across the country, ranging from wind chill values of -55 in some Arctic regions to -30 in southwestern Ontario.

Blizzard Warning

  • Issued if strong winds, cold temperatures and reduced visibilities from snow or blowing snow are expected to persist for four hours or more (6 more hours in the North).

Tornado Warning

  • Issued when one or more tornadoes or funnel clouds are observed or detected on Doppler radar.

Tropical Storm Warning

  • Issued when an approaching tropical cyclone is expected to produce winds of 63 to 118 km/h.

Hurricane Warning

  • Issued when an approaching tropical cyclone is expected to produce winds greater than 118 km/h.

Weather Reports: Tornadoes

About 80 tornadoes are reported in Canada each year. Most are too weak to cause serious damage. The strength of a tornado is determined by the damage it causes to buildings and structures, using a scale developed by Dr. Ted Fujita, a pioneer of research in tornadoes. The scale used today in Canada is called the Enhanced Fujita Scale and it ranges from EF0 to EF5. This scale is an updated version of the original Fujita Scale. Meteorologists, architects and engineers determined how strong a wind has to be to inflict damage on a certain type of structure. There has only been one recorded occurrence of an EF5 tornado in Canada on June 22, 2007 in Elie, Manitoba. The damages from this tornado were estimated at 39 million dollars.

ScaleWind SpeedDamage
EF090-130 km/hOverturns garden sheds, and breaks large branches
EF1135-175 km/hBreaks glass in doors and windows, rips off shingles
EF2180-220 km/hRemoves large sections of roof and collapses the walls of barns
EF3225-265 km/hUpper storeys of brick houses destroyed, outer walls removed from most houses
EF4270-310 km/hTwo-storey brick houses almost destroyed, cars and vans carried long distances
EF5315 km/h or moreDestroys virtually everything in its path

Weather Reports: Hurricanes

Hurricanes are classified by the strength of their winds using the Saffir-Simpson Scale. A Category 1 hurricane has the lowest wind speeds and a Category 5 the highest. No Category 3, 4 or 5 hurricane has made landfall in Canada in over a century.

Saffir-Simpson Hurricane Scale
CategoryWind Speed (km/h)
1119--153
2154--177
3178--210
4211--249
5> 249

Tropical storms or hurricanes that have severe impacts, either on lives or on the economy, are usually remembered many years after the devastation. These storms become part of weather history. Many feel that, in these cases, reusing the name of such a devastating storm in the future would lack compassion and sensitivity. On April 29, 2004, the World Meteorological Organization granted Canada’s request to retire the name Juan, a Category 2 hurricane which was the most powerful storm to hit Nova Scotia and Prince Edward Island in over a century. This was the first time that Canada had requested the retirement of a storm name.

More information about Canadian hurricanes is available from Environment and Climate Change Canada’s Canadian Hurricane Centre website.

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4.4 Reflect

What Does Wind Mean to Me?

If You Are Camping

Pay attention to the forecast when you plan a camping trip, and be prepared for unexpected weather. Pick out a safe refuge near your campsite in case you need shelter from severe weather. Shelter might include a comfort station, shower facility or a low spot in a thick stand of trees.

Cold Weather Winds

Frostbite and hypothermia (low body temperature) occur when more heat is lost than your body can generate. Although this happens more rapidly on a windy winter day, don’t be fooled--you need to guard against frostbite on any cold winter day.  

Cold Weather Safety Tips for Kids

  • Limit your time outdoors when the temperature is extremely cold.
  • Dress appropriately and cover your head, ears and face.
  • Use the “buddy” system. You and a friend can check exposed skin on each other’s face for tell--tale white patches where skin is frozen. If you spot frostbite, go indoors immediately for help.
  • Keep active. Physical activity generates more body heat.
  • Stay dry. Wet clothing speeds up the loss of body heat. If your mitts or boots are wet, go indoors to change them.

Warm Weather Winds

Tornado Safety Tips For Kids  

Tornadoes most often occur in the afternoon or early evening from May to September. Play it safe if you see a funnel cloud, or if you hear that a tornado warning has been issued for your area.

  • When a tornado threatens take shelter immediately--preferably in the lower level of a sturdy building.
  • Stay away from windows and doors--flying glass and debris poses the greatest danger.
  • In a house, go to the basement or take shelter in a small room on the ground floor such as a bathroom or closet. If that is not possible then shelter under a sturdy desk or table.

Hurricane Hazards

The hazards commonly associated with hurricanes include high winds, storm surges and flooding from intense rainfalls. A storm surge is a swelling of water driven by the strong winds and low pressure of the hurricane. Storm surges can move very far inland and cause extensive damage to buildings, vehicles and people. Storm surges are frequently one of the most overlooked and misunderstood hazards of a hurricane. This surge of water can combine with the normal tide and increases the average water level by 5 m or more.

Hurricane Safety Tips for Children  

  • During hurricane season, pay attention to weather forecasts and warnings.
  • If you live on the coast or in a low-lying area near the coast, move inland and to higher ground. The high winds create huge waves at sea which can be very damaging when combined with a storm surge
  • Do not go down to the water to watch the storm. Most fatalities during hurricanes occur as a result of being caught in large waves, storm surges or flood waters.

Wind Carries Air Pollution

Maritime Provinces

New Brunswick, Nova Scotia and Prince Edward Island receive air pollution from the Lower Great Lakes Region, southern Quebec and the eastern seaboard of the United States. Cross-border pollution, due to long-range transport, is the major contributor to this region’s smog problem.

Windsor-Quebec City Corridor

This heavily populated corridor covers a strip about 100 km wide along the Canadian border, extending from Windsor through Toronto and Montreal to Quebec City. This area experiences high levels of ground-level ozone more often and for longer periods than any other part of the country. While much of the smog here is generated locally, air pollution transported from the United States contributes significantly to ground-level ozone in the region.

Lighthouse

Description

Rays of sun and wisps of cloud above an Atlantic Canadian lighthouse. Most of the smog in the Maritime Provinces forms elsewhere.

Lower Fraser Valley

This valley, which includes the City of Vancouver, is bordered by the Coastal Mountains to the north and the Cascade Mountains to the southeast. These unique geographical features, along with the sea-to-shore breezes off the Strait of Georgia, restrict air-flow patterns and contribute to the area’s ground-level ozone problem. Here, the majority of the smog is generated locally. Motor vehicles in the Vancouver area are one of the major sources of smog in this region.

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Curriculum

Alberta

Correlation of Sky Watchers to the Alberta Science Curriculum Topic D: Weather Watch Specific Curriculum Outcomes

Processes

Each section of the newly adapted guide includes observing, predicting and reflection. These processes are important in Canadian provincial and territorial curricula.

Observe

  • Describe and demonstrate methods for measuring wind speed and for finding wind direction.
  • Measure at least four different kinds of weather phenomena. Either student-constructed or standard instruments may be used.

Predict

  • Predict where, within a given indoor or outdoor environment, one is likely to find the warmest and coolest temperatures.
  • Appreciate how important it is to be able to forecast weather and to have suitable clothing or shelter to endure various types of weather.

Reflect

  • 5-9 Investigate relationships between weather phenomena and human activity.
  • (General Learner Expectation, GLE)
  • Appreciate how important it is to be able to forecast weather and to have suitable clothing or shelter to endure various types of weather.
  • Test fabrics and clothing designs to choose those with characteristics that most effectively meet the challenges of particular weather conditions; e.g., water resistance, wind resistance, protection from cold.

Read with Understanding

Each section of the guide highlights different topics and curricular themes.

Alberta
1. Energy2. Water Vapour3. Precipitation4. Wind
  • 5-8 Observe, describe and interpret weather phenomena; and relate weather to the heating and cooling of the Earth’s surface. (GLE)
  • Describe the effects of the Sun’s energy on daily and seasonal changes in temperature-- 24-hour and yearly cycles of change.
  • Recognize that weather systems are generated because different surfaces on the face of Earth retain and release heat at different rates.
  • Describe evidence that air contains moisture and that dew and other forms of precipitation come from moisture in the air.
  • Identify some common types of clouds, and relate them to weather patterns.
  • Describe and measure different forms of precipitation, in particular, rain, hail, sleet, snow.
  • 5-8 Observe, describe and interpret weather phenomena; and relate weather to the heating and cooling of the Earth’s surface. (GLE)
  • Describe patterns of air movement, in indoor and outdoor environments, that result when one area is warm and another area is cool.

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British Columbia and Yukon

Correlation of Sky Watchers to the British Columbia Science Curriculum – Grade 4 Earth and Space Science The British Columbia program of studies forms the basis of the Yukon curriculum.
Prescribed Learning Outcomes

Processes

Each section of the newly adapted guide includes observing, predicting and reflection. These processes are important in Canadian provincial and territorial curricula.

Observe

  • Measure weather in terms of temperature, precipitation, cloud cover, wind speed and direction
  • Weather conditions that can be observed and/or measured include temperature, wind speed, wind direction, precipitation, air pressure and cloud formations
  • Observe weather conditions and record using graphs, tables and charts
  • Construct simple instruments

Predict

  • Interpret data from recorded observations
  • Predict weather conditions

Reflect

  • Analyse impacts of weather on living and non-living things
  • Weather conditions affect living things (e.g., growth, behaviour, food, shelter)
  • Weather conditions (e.g., erosion) affect non-living things

Read with Understanding

Vocabulary

Temperature, wind speed, wind direction, water cycle, cloud, evaporation, condensation, precipitation, erosion, barometer, anemometer, thermometer, rain gauge, weather vane

Each section of the guide also highlights different topics and curricular themes.

British Columbia and Yukon
1. Energy2. Water Vapour3. Precipitation4. Wind
  • The surface of the planet Earth is surrounded by a blanket of air called the atmosphere
  • The Earth’s surface is heated by energy from the Sun
  • Most of the Earth’s surface is covered by water and circulates through the water cycle
  • Most of the Earth’s surface is covered by water and circulates through the water cycle
_

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Manitoba

Correlation of Sky Watchers to the Manitoba Science Curriculum--Grade 5 Weather (Cluster 4)

Specific Learning Outcomes

Processes

Each section of the newly adapted guide includes observing, predicting and reflection. These processes are important in Canadian provincial and territorial curricula.

Observe

  • 5-4-05 Use the design process to construct a weather instrument.
    Examples: an instrument that measures wind direction, wind speed, rainfall
    GLO: C3,D5
  • 5-4-06 Observe and measure local weather conditions over a period of time, using student-constructed or standard instruments, and record and analyze these data.
    GLO: A2,C2,C5,D5
  • 5-4-07 Identify and describe components of public weather reports from a variety of sources.
    Include: temperature; relative humidity; wind speed and direction; wind chill; barometric pressure; humidex; cloud cover; ultraviolet index; warm and cold fronts; amount, types, and probability of precipitation
    GLO: C6,D5
  • 5-4-08 Describe the key features of a variety of weather phenomena.
    Examples: wind speed and precipitation of blizzards
    GLO: D5,E1,E2

Predict

  • 5-4-10 Investigate various ways of predicting the weather, and evaluate their usefulness.
    Examples: weather-related sayings, traditional knowledge, folk knowledge, observations of the natural environment
    GLO: A2,A4,B2,C8
  • 5-4-12 Describe examples of technological advances that have enabled humans to deepen their scientific understanding of weather and improve the accuracy of weather predictions.
    Examples: satellites collect data that scientists analyze to increase understanding of global weather patterns; computerized models predict weather
    GLO: A2,A5,B1,D5

Reflect

  • 5-4-02 Describe how weather conditions may affect the activities of humans and other animals.
    Examples: heavy rainfall may cause roads to wash out; stormy conditions may prevent a space shuttle launching; in excessive heat, cattle may produce less milk
    GLO: D5
  • 5-4-09 Provide examples of severe weather forecasts, and describe preparations for ensuring personal safety during severe weather and related natural disasters.
    Examples: tornado, thunderstorm, blizzard, extreme wind chill, flood, forest fire
    GLO: B3, C1, D5

Read with Understanding

  • 5-4-01 Use appropriate vocabulary related to their investigations of weather.
    Include: weather; properties; volume; pressure; air masses; fronts; weather instrument; severe weather; forecast; accuracy; water cycle; climate; terms related to public weather reports and cloud formations
    GLO: C6,D5

Each section of the guide also highlights different topics and curricular themes.

Manitoba
1. Energy2. Water Vapour3. Precipitation4. Wind
  • 5-4-13 Explain how the transfer of energy from the Sun affects weather conditions.
  • Include: the Sun’s energy evaporates water and warms the Earth’s land, water and air on a daily basis

GLO: D4,D5,E4

5-4-13 Explain how the transfer of energy from the Sun affects weather conditions. Include: the Sun’s energy evaporates water and warms the Earth’s land, water and air on a daily basis GLO: D4,D5,E4 5-4-14 Explain how clouds form, and relate cloud formation and precipitation to the water cycle. GLO: D5,E2 5-4-15 Identify and describe common cloud formations. Include: cumulus, cirrus, stratus GLO: D5, E15-4-14 Explain how clouds form, and relate cloud formation and precipitation to the water cycle. GLO: D5,E25-4-03 Describe properties of air. Include: has mass/weight and volume; expands to fill a space; expands and rises when heated; contracts and sinks when cooled; exerts pressure; moves from areas of high pressure to areas of low pressure GLO: D3 5-4-04 Recognize that warm and cold air masses are important components of weather, and describe what happens when these air masses meet along a front. Include: in a cold front the cold air mass slides under a warm air mass, pushing the warm air upwards; in a warm front the warm moist air slides up over a cold air mass GLO: D5, E2

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New Brunswick (Anglophone), Newfoundland, Labrador and Prince Edward Island

Correlation of Sky Watchers to Prince Edward Island, Newfoundland, Labrador and New Brunswick Science Curriculum – Grade 5 Earth and Space Science: Weather

Specific Learning Outcomes

Processes

Each section of the newly adapted guide includes observing, predicting and reflection. These processes are important in Canadian provincial and territorial curricula.

Observe

  • identify and/or construct, and use instruments for measuring weather information (204-8, 205-4, 205-10)
  • use appropriate terminology in naming weather instruments and collecting weather data (104-7)
  • record observations using measuring instruments in order to describe weather in terms of temperature, wind speed, wind direction, precipitation and cloud cover (205-7, 300-13)
  • estimate weather measurements for various times of the day, week or for weather systems (205-6)
  • compile and display weather data collected over a period of time in table and/or graph format, and identify and suggest explanations for patterns or discrepancies in the data (206-2, 206-3)

Predict

  • identify and use weather-related folklore to predict weather (105-2)
  • use a variety of sources to gather information to describe the key features of a variety of weather systems (205-8, 302-11)
  • identify weather-related technological innovations and products that have been developed by various cultures in response to weather conditions (107-14)
  • ask different people in the community and region for advice on how to predict weather, and compare the tools and techniques they use to make predictions (107-2, 107-10, 207-4)
  • identify positive and negative effects of technologies that affect weather and the environment (108-1)

Reflect

  • identify and use appropriate tools, measuring instruments and materials to measure the temperature of soil and water after exposing them to light and draw conclusions (204-8,
    205-4, 206-5)
  • provide examples of ways that weather forecasts are used by various people in their community (107-5)

Read with Understanding

Each section of the guide also highlights different topics and curricular themes.

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New Brunswick (Anglophone), Newfoundland, Labrador and Prince Edward Island
1. Energy2. Water Vapour3. Precipitation4. Wind
  • Relate the transfer of energy from the sun to weather conditions (303-21)
  • Classify clouds as stratus, cumulus, cirrus, or “other”, compare results with others, and recognize that results may vary (104-4, 206-1)
  • Relate the constant circulation of water on Earth to the processes of evaporation, condensation, and precipitation
    (301-13)
  • Relate the constant circulation of water on Earth to the processes of evaporation, condensation and precipitation
    (301-13)
  • Describe situations demonstrating that air takes up space, has mass and expands when heated (300-14)
  • Identify patterns in indoor and outdoor air movement
    (302-10)

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New Brunswick (Francophone)

Correlation of Sky Watchers to New Brunswick Science Curriculum – Grades 3 to 5

Specific Learning Outcomes

Processes

Each section of the newly adapted guide includes observing, predicting and reflection. These processes are important in Canadian provincial and territorial curricula.

Observe

N/A

Predict

The Earth

4.4 Identify the various features of a weather report (e.g., temperature, wind speed, precipitation, cloud cover)

Reflect

N/A

Read with Understanding

Each section of the guide also highlights different topics and curricular themes.

New Brunswick (Francophone)
1. Energy2. Water Vapour3. Precipitation4. Wind

Matter and Energy

  • 4.12 Identify various natural sources of energy (sun, oil, coal, plants, food, nuclear, water, wind)
--

The Earth

  • 6.6 Understand that changes occur in various ways all the time (regular, repetitive or irregular); sometimes, change occurs in different ways at the same time
    (e.g., waves, tides, tsunami, wind, earthquakes)

Space

  • 5.11 Describe how air affects everything around us

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Nova Scotia

Correlation of Sky Watchers to the Nova Scotia Science Curriculum Draft – Grade 5 Earth and Space Science: Weather

Specific Learning Outcomes

Processes

Each section of the newly adapted guide includes observing, predicting and reflection. These processes are important in Canadian provincial and territorial curricula.

Observe

  • Using correct names of weather instruments, construct and use instruments to record temperature, wind speed, wind direction, and precipitation (104-7, 204-8, 205-4, 205-10,
    205-7, 300-13)

Predict

  • Identify and use weather-related folklore to predict weather (105-2)
  • Using a variety of sources, gather information to describe the key features of weather systems and identify weather-related technological innovations and products that have been developed by cultures in response to weather conditions (107-14, 205-8, 302-11)

Reflect

  • Using a variety of sources, gather information to describe the key features of weather systems and identify weather-related technological innovations and products that have been developed by cultures in response to weather conditions (107-14, 205-8, 302-11)

Read with Understanding

Each section of the guide also highlights different topics and curricular themes.

Nova Scotia
1. Energy2. Water Vapour3. Precipitation4. Wind
  • Relate the transfer of energy from the sun to weather and discuss the sun’s impact on soil and water (206-5, 303-21)
  • Identify, classify and compare clouds  (104-4, 206-1)
  • Relate the constant circulation of water on Earth to the processes of evaporation, condensation, and precipitation (301-13)
  • Relate the constant circulation of water on Earth to the processes of evaporation, condensation, and precipitation
  • (301-13)
  • Describe situations demonstrating that air takes up space, has mass and expands when heated (300-14)

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Nunavut

Correlation of Sky Watchers to the Nunavut Science Curriculum – Grade 6 Weather

Concepts, Processes, and Skills

Processes

Each section of the newly adapted guide includes observing, predicting and reflection. These processes are important in Canadian provincial and territorial curricula.

Observe

1a) To keep records of weather.

1b) To observe the special weather situation during each season, e.g., snow and ice, flooding, drought, thunder storms.

2a) To observe the effects of the wind.

3. Wind speed can be measured by wind gauges.

3a) To make a wind gauge and measure the wind speed.

14b) To observe cloud formation.

15b) To construct and calibrate a rain gauge.

Predict

2b) To infer direction of air currents.

14c) To predict the weather based on cloud formations.

Reflect

N/A

Read with Understanding

1. Weather consists of interacting factors such as temperature, pressure, precipitation, humidity and wind.

Each section of the guide also highlights different topics and curricular themes.

Nunavut
1. Energy2. Water Vapour3. Precipitation4. Wind
-

4. Warm air rises and is replaced by cooler, heavier air.

5. Water evaporates into the air, and in the process, absorbs energy.

5a) To predict and demonstrate that water evaporating cools an object (absorbs energy).

9. Water vapour becomes liquid when it condenses.

12. Air contains varying amounts of water.

12a) To identify sources of water vapour.

13. Water vapour in the air can be measured (relative humidity).

13a) To explain how relative humidity is measured.

14. Clouds form when moisture-laden air rises.

14a) To demonstrate cloud formation.

15. Rain forms when clouds are cooled.

15a) To prepare a model to simulate cloud formation and rainfall.

2. Wind is caused by the movement of air masses.

4. Warm air rises and is replaced by cooler, heavier air.

4a) To infer that warm air rises because, in warming, it expands and takes up more space.

4b) To hypothesize that air expands when warmed.

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Ontario

Ontario Ministry of Education removed weather from its late elementary curriculum effective September 2008.

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Quebec

Correlation of Sky Watchers to the Quebec Science and Technology Curriculum

Processes

Each section of the newly adapted guide includes observing, predicting and reflection. These processes are important in Canadian provincial and territorial curricula.

Observe

Build on tools, objects and procedures used in science and technology

Earth and Space: Techniques and Instrumentation

– Design/construction of measurement instruments and prototypes

– Use of simple measurement instruments (e.g., rulers, scale, thermometer, weather vane, barometer, wind gauge, hygrometer)

Predict

Earth and Space: Systems and Interaction

– Earth, atmospheric and space technologies (e.g., seismograph, prospecting, weather forecasting, satellites, space station)

Reflect

Propose explanations or solutions to scientific problems

Read with Understanding

Overall

Communicate using appropriate scientific and technical terminology

Each section of the guide also highlights different topics and curricular themes.

Quebec
1. Energy2. Water Vapour3. Precipitation4. Wind

Earth and Space: Systems and Interaction

  • Seasons
    (Cycle 3 only)

Earth and Space: Energy

  • Energy sources: solar energy
  • Energy transmission (e.g., radiation

Earth and Space: Force and Movement

  • The Earth's rotation (e.g., day and night, apparent movement of Sun and stars)

Earth and Space: Matter

  • Natural phenomena (e.g., erosion, thunder)

Earth and Space: Systems and Interaction

  • Weather systems (e.g., clouds, precipitation, storms and climates)

Earth and Space: Matter

  • Natural phenomena
    (e.g., erosion, thunder)

Earth and Space: Systems and Interaction

  • Weather systems (e.g., clouds, precipitation, storms and climates)

Earth and Space: Systems and Interaction

  • Weather systems
    (e.g., clouds, precipitation, storms and climates)

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Saskatchewan

Correlation of Sky Watchers to the Saskatchewan Science Curriculum – Grade 4 Predicting Weather

Science Foundational and Learning Objectives

Processes

Each section of the newly adapted guide includes observing, predicting and reflection. These processes are important in Canadian provincial and territorial curricula.

Observe

  • Observe and describe weather conditions.
    1.3. Identify instruments used to measure weather conditions.
    1.4. Construct instruments to measure weather conditions.
    1.5. Record measurements made with weather instruments.

Predict

  • Predict weather patterns.
    2.3. Interpret recorded data.
    2.4. Predict weather based on a number of different indicators.

Reflect

  • Appreciate the importance of weather.
    3.1. Suggest some reasons why people rely on accurate weather information.
    3.2. Explain the importance of good weather to agriculture.
    3.3. Identify some hazards associated with bad weather.
    3.4. Describe some ways in which the weather affects human activity.
    3.5. Describe some ways in which the weather affects other living things.

Read with Understanding

Each section of the guide highlights different topics and curricular themes.

Saskatchewan
1. Energy2. Water Vapour3. Precipitation4. Wind
-
  • 1.2. Forecast weather based on cloud patterns.
-
  • 1.1. Discover how weather systems develop.

Top of Page


Northwest Territories

Correlation of Sky Watchers to the Northwest Territories Science and Technology Curriculum – Grade 5 Earth and Space Systems

Specific Learning Outcomes

Processes

Each section of the newly adapted guide includes observing, predicting and reflection. These processes are important in Canadian provincial and territorial curricula.

Observe

  • Design, construct and test a variety of weather instruments (e.g., weather vane, anemometer, rain gauge, wind sock, hydrometer);
  • Compile data gathered through investigation in order to record and present results, tally charts, tables, and labeled graphs produced by hand or with a computer (e.g., record both qualitative and quantitative data from observations of weather over a period of time; accurately use a thermometer to read and record the results);

Predict

  • Predict local weather patterns using data from their own observations of weather and from weather reports;
  • Explain how advances in technology and science enable humans to make predictions about weather (e.g., satellite images of the Earth allow us to track weather patterns on a larger scale; computer modelling and automated weather stations);
  • Understand and explain the importance of weather forecasting for people in certain occupations (e.g., fishers, hunters, farmers, pilots);

Reflect

  • Formulate questions about and identify needs and problems related to objects and events in the environment, and explore possible answers and solutions (e.g., test a variety of fabrics for their waterproofing or insulating properties)
  • Plan investigations for some of these answers and solutions, identifying variables that need to be held constant to ensure a fair test and identifying criteria for assessing solutions
  • Communicate the procedures and results of investigations for specific purposes and to specific audiences, using electronic media, oral presentations, written notes and descriptions, drawings, and charts (e.g., draw a labelled diagram of the water cycle)
  • Describe ways in which weather conditions affect the activities of humans and other animals (e.g., people refrain from strenuous physical activity in extreme heat; animals hibernate in extreme cold; animal fur thickens with cold weather);
  • Explain how climatic and weather conditions influence the choice of materials used for building shelters (e.g., wood/bricks are often used for building in cold climates, stone and marble in warmer climates).

Read with Understanding

Vocabulary

Use appropriate vocabulary, including correct science and technology terminology, in describing their investigations and observations (e.g., use terms such as temperature, precipitation, relative humidity, wind chill factor, barometric pressure and cloud cover).

Each section of the guide also highlights different topics and curricular themes.

Northwest Territories
1. Energy2. Water Vapour3. Precipitation4. Wind
  • Describe the ways in which energy from the sun affects weather conditions
    (e.g., evaporation of water results in condensation, which in turn results in precipitation)
  • Explain the formation of clouds and the effects of different cloud formations on weather and climate
  • Describe the water cycle in terms of evaporation, condensation and precipitation
  • Describe the ways in which energy from the sun affects weather conditions
    (e.g., evaporation of water results in condensation, which in turn results in precipitation)
  • Identify and describe the major cloud types/formations
  • Describe the water cycle in terms of evaporation, condensation and precipitation
  • Describe the ways in which energy from the sun affects weather conditions
    (e.g., evaporation of water results in condensation, which in turn results in precipitation)
  • Recognize large-scale and local weather systems
    (e.g., fronts, air masses, storms)
  • Identify patterns in air movement
    (e.g., low pressure and high pressure)
  • Identify the effects of air pressure
    (e.g., low pressure air masses are associated with mild temperature and create conditions that cause thunderstorms or clouds; high pressure air masses are cooler and are often associated with clear weather conditions)
  • Recognize how the movement of large- scale air masses affects regional weather in the NWT
    (e.g., Arctic high pressure systems are associated with clear and cold weather; Atlantic systems are associated with cloudy skies; Pacific systems are associated with a wide variety of weather conditions)

Return to Table of Contents

References and Related Publications

References

Air Quality Health Index. Environment Canada, 16 Jul 2013. Web. 15 Feb 2013.

Allen, Oliver E. Atmosphere. The Planet Earth Series. Alexandria, Virginia: Time-Life Books, 1983.

Canadian Hurricane Centre. Environment Canada. Web. 01 Mar 2012.

Casselman, A., Berry, A., Hain, D. and Fergusson, A. 2002. Solar UV in our World: Secondary Education Information and Investigations. Public Works and Government Services Canada.

Dermatologists Applaud British Columbia Tanning Ban. Canadian Dermatology Association. Web. 15 Oct 2012.

Dickinson, Terence. Exploring the sky by day: the Equinox guide to weather and the atmosphere. Camden East, ON: Camden House, 1989.

Encyclopedia Britannica. Web. 21 Nov 2013.

Engelbert, Phillis. The Complete Weather Resource. 3 vols. Detroit: U.X.L., 1997. Vol.3. Forecasting and Climate.

Environment Canada. A Matter of Degrees: A Primer on Climate Change. Ottawa: Environment Canada, 1997.

Environment Canada. Ice Storm '98: January 4-10, 1998. Ottawa: Environment Canada, 1998.

Environment Canada. Learning Weather Kit. 2 vols. Ottawa: Environment Canada. Vol 1. Knowing Weather: Facts and Myths.

Environment Canada. Sky Watchers Guide: Pacific and Yukon Region. Vancouver: Environment Canada.

Environment Canada. Weather Watchers Teachers' Guide. Edmonton: Environment Canada, 1997.

Environment Canada. Wind, Weather & Waves: A Guide to Marine Weather in the Great Lakes region. Ottawa: Environment Canada, 1998.

Environment Canada, Atlantic Region. East Coast Marine, Weather Manual: A guide to local forecasts and conditions. Ottawa: Minister of Supply and Services, 1989.

Guide to Environment Canada's Public Forecasts. Environment Canada, 4 Jul 2013. Web. 21 Nov 2013.

Ludlum, David, M. The Audubon Society Field Guide to North American Weather. New York: Alfred A Knopf, 1991.

Miami Science Museum. Web. 2013.

Phillips, David. The Climates of Canada. Ottawa: Ministry of Supply and Services, 1990

Phillips, David. The Day Niagara Falls Ran Dry. Toronto: Key Porter Books Ltd., 1993.

Phillips, David. Blame it on the Weather: Canadian Strange Weather Facts. Toronto: Key Porter Books Ltd., 1998.

Pommainville, Pierre. Aware: Aviation Weather Already for Emergency. 2nd ed. St. Hubert: Environment Canada, Quebec Region. 1996.

Schonland, Sir Basil. The Flights of Thunderbolts. 2nd ed. Oxford: Claredon Press, 1964.

Rossetti, Christina. 1947. Who Has Seen the Wind? Poetry Foundation. n.d.

Sun Safety. Government of Canada, 12 Jan 2012. Web. 1 Feb 2013.

Tanning and its Effects on Your Health. Health Canada, Sep 2012. Web. 1 Feb 2013.

Frequently asked questions about the Air Quality Health Index (AQHI). Environment Canada, 13 Nov 2013. Web. 21 Nov 2013.

The Globe Program. UCAR Community Programs, n.d. Web. 1 Feb 2013.

The Hydrologic Cycle. Environment Canada, 9 Sept 2013. Web. 21 Nov 2013.

The UV Index & Your Local Forecast. Health Canada, 15 Dec 2008. Web. 1 Jan 2013.

Preventing Skin Cancer. Health Canada, 23 Sep 2011. Web. 15 Feb 2013.

UV Index Sun Awareness Program. Health Canada, 1 Feb 2013. Web. 15 Feb 2013.

Weather Office. Environment Canada, 19 Jan 2013. Web. 29 Jan 2013.

Williams, Jack. The Weather Book: An Easy to Understand Guide to the USA's Weather. New York: Vintage Books, 1992.

Wood, Richard, A., ed. The Weather Almanac. Detroit: Gale Research, 1996.

Wyman Brenda. Weather. Cypress, California: Creative Teaching Press, 1995.

Wyatt, Valerie. Weather Watch. Toronto: Kids Can Press Ltd., 1990.

Top of Page


Related Publications

Grades K--3

Brandt, Keith. What makes it rain: the story of a raindrop. Illus. By Yoshi Miyake.
Mahwah, NJ: Troll Communications, 1996.
ISBN 0-89375-583-4 (K-3)

Branley, Franklyn M. Down comes the rain. Illus. by James Graham Hale.
New York: HarperCollins Publishers, 1997.
(Let's-read-and-find-out science books)

Burby, Lisa N. Heat waves and droughts. 1st ed.
New York: PowerKids Press, 1999.
ISBN 0-8239-5292-4 (2-4)

Butler, Daphne et Denis-Paul Mawet. Pourquoi le vent souffle-t-il? Montréal : Les Éditions École Active, 1994.
ISBN 2-89069-440-2 (K-3)

Butler, Daphne. What happens when wind blows?
Austin, TX: Raintree Steck-Vaughn, 1996.
ISBN 0-817241531 (K-3)

Cole, Joanna. The magic school bus inside a hurricane.
New York: Scholastic Inc., 1995.
ISBN 0-590-44686-X (K-3)

Cooper, Kay. Too many rabbits and other fingerplays: about animals, nature, weather and the universe.
New York; Toronto: Scholastic, 1995.
ISBN 0-590-45564-8 (K-1)

Craig, Jean M. Questions and answers about weather.
New York: Scholastic Inc., 1996.
ISBN 0-59041142-X (K-3)

Dorion, Christiane. How the weather works: a hands-on guide to our changing climate.
Somerville: Candlewick Press, 2011.
ISBN 9780763652623 (2-6)

Gillis, Jennifer Storey. Puddle jumpers: fun weather projects for kids. Illustrations by Patti Delmonte.
Pownal, Vt.: Storey Communications, 1996.
ISBN 0-88266-938-9 (pbk) (2-4)

Hewitt, Sally. Weather.
New York: Children's Press, 2000. (It's science!)
ISBN 0-516-21657-0 (1-3)

Hiscock, Bruce. When will it snow?
New York: Atheneum, 1995.
ISBN 0-689-31937-1 (2-4)

Hopkins, Lee Bennett. Weather. Poems selected by Lee Bennett Hopkins.
New York: HarperCollins, 1994. (An I can read book)
ISBN 0-06-021463-5 (K-2)

Humphrey, Paul. Weather. Illus. by roger Stewart and Shirley Tourret.
London; New York: Children's Press, 1997. (Step-by-step geography)
ISBN 0-516-20238-3 (K-3)

Krupp, Edwin C. The rainbow and you. Illus. by Robin Rector Krupp.
New York: HarperCollins Publishers, 2000.
ISBN 0-688-15601-0 (2-4)

Llewellyn, Claire. Why do we have wind and rain?
London: Hamlyn, 1995.
ISBN 0-60058522 (K-3)

Malam, John. Wacky weather. Illus. by Mike Foster.
Toronto: Macmillan Canada, 1998, 1997. (How it works)
ISBN 0-7715-7565-3 (2-4)

Martin, Terry. Pourquoi il y a des éclairs? : et autres questions sur la météo.
Richmond Hill, Ont. : Éditions Scholastic, 1997.
ISBN 0-590-16684-0 (K-3)

Martin, Terry. Why does lightning strike? : questions children ask about the weather.
Richmond Hill, Ont.: Scholastic Canada, 1996.
ISBN 0-590-24945-2 (K-3)

Owen, Andy. Rain. Andy Owen and Miranda Ashwell.
Des Plaines, ILL: Heinemann Library, 1999. (What is weather?)
ISBN 1-57572-789-7 (K-3)

Owen, Andy. Watching the weather. Andy Owen and Miranda Ashwell.
Des Plaines, Ill.: Heinemann Library, 1999. (What is weather?)
ISBN 1-57572-792-7 (K-3)

Petty, Kate. People chase twisters. Illustrators, Peter Roberts and Jo Moore.
Brookfield, Conn.: Copper Beech Books, 1998.
ISBN 0-7613-0715-X (lib. bdg.)
ISBN 0-7613-0647-1 (trade) (2-4)

Rowe, Julian and Molly Perham. Weather watch!
Chicago: Children's Press, 1994. (First science)
ISBN 0-516-48142-8 (1-4)

Simon, Seymour. Lightning.
New York: Morrow, 1997.
ISBN 0-688-14639-2 (hc)
ISBN 0-688-16706-3 (pbk) (K-3)

Simon, Seymour. Tornadoes.
New York: Morrow, 1999.
ISBN 0-688-14646-5 (hc)
ISBN 0-688-14647-3 (pbk) (2-4)

Singer, Marilyn. On the same day in March: a tour of the world's weather. Illus. by Frané Lessac.
New York: HarperCollins Publishers, 2001.
ISBN 9780064435284

Wallace, Karen. Whatever the weather.
Bolton, Ont.: Fenn Publishing Ltd., 1999. (Know it all readers. Level 1)
ISBN 1-55168-215-X (PreS-1)

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Grades 4-6

Archer, Cheryl. Snow watch.
Toronto: Kids Can Press, 1994.
ISBN 1-55074-190-X (4-6)

Arnold, Caroline. El Niño: stormy weather for people and wildlife.
New York: Clarion Books, 1998.
ISBN 0-395-77602-3 (5-7)

Artell, Mike. Weather whys: questions, facts and riddles about weather.
Glenview, IL: GoodYearBooks, 1995.
ISBN 0-673-36173-X (4-6)

Beecroft, Simon. The new book of El Niño.
Brookfield, Conn.: Copper Beech Books, 1999.
ISBN 0-7613-0920-9 (lib. bdg.)
ISBN 0-7613-0797-4 (pbk.) (4-6)

Bender, Lionel. Heat and drought.
Austin, Tex.: Raintree Steck-Vaughn, 1998. (Living with the weather)
ISBN 0-8172-5051-4 (4-6)

Breen, Mark. The kids' book of weather forecasting: build a weather station, "read" the sky & make predictions. With meteorologist Mark Breen and Kathleen Friestad.
Charlotte, VT: Williamson Publishing, 2000. (A Williamson kids can! Book)
ISBN 1-885593-39-2 (4-6)

Carroll, Colleen. The weather: sun, wind, snow, rain.
1st ed. New York: Abbeville Kids, 1996. (How artists see)
ISBN 0-7892-0031-7
ISBN 0-7892-0478-9 (library ed.) (4-7)

Casey, Denise. Weather everywhere.
New York: Macmillan, 1995.
ISBN 0-02-717777-7 (4-6)

Christian, Spencer. Can it really rain frogs? the world's strangest weather events.
New York: Wiley, 1997.
ISBN 0-471-15290-0 (4-6)

Dorion, Christiane. How the weather works: a hands-on guide to our changing climate.
Somerville: Candlewick Press, 2011.
ISBN 9780763652623 (2-6)

Elsom, Derek. Weather: an accessible guide that really explains the elements.
London: Marshall Publishing, 1997. (Your world explained)
ISBN 1-84028-158-8 (4-6)

Farndon, John. Weather: how to watch and understand the weather and its changes.
Toronto: Stoddart Pub. Co., 1992. (Eyewitness explorers)
ISBN 0-7737-2581-4
ISBN 1-56458-019-9 (4-6)

Fergusson, Angus. The UV Index, weather & you : the UV Index Children's Sun Awareness Program:
activity information guide.
Downsview, ON: Science Assessment and Integration Branch, Meteorological Service of Canada, 2000.
ISBN 0-662-28949-8
Govt. Cat. No. EN56-154 /2000E (5-8)

Fergusson, Angus. L'indice UV, le temps & vous : Programme de l'indice UV pour la sensibilisation des enfants aux effets du soleil : guide d'activités d'information.
Downsview, ON: Direction de l'évaluation et de l'intégration scientifique, Service météorologique du Canada, 2000.
ISBN 0-662-84694-X
Govt. Cat. No. EN56-154 /2000F (5-8)

Flint, David. Météorologie et climat.
Saint-Lambert, Québec: Héritage, 1994.
ISBN 2-713016150 (4-6)

Harper, Suzanne. Clouds: from mare's tails to thunderheads.
New York: Franklin Watts, 1997. (First books)
ISBN 0-531-20291-7 (4-6)

Harper, Suzanne. Lightning.
New York: Franklin Watts, 1997. (First books)
ISBN 0-531-20290-9 (4-6)

Holub, Joan and Julie Hanna. The Man Who Named The Clouds.
Park Ridge, Illinois: Albert Whitman & Co, 2006.
ISBN 9780807549742 (3-5)

Jennings, Terry. Weather.
Jersey City, N.Y.: Park West Publications, 1999.
ISBN 0-563-37382-2 (3-5)

Jones, Lorraine. Super science projects about weather and natural forces.
New York: Rosen Publishing Group, 2000. (Psyched for science)
ISBN 0-8239-3105-6 (3-5)

Kahl, Jonathan D.W. Hazy skies: weather and the environment.
ISBN 0-8225-2530-5 (5-8)

Kahl, Jonathan D.W. Weather watch: forecasting the weather.
ISBN 0-8225-2529-1 (5-7)

Kerrod, Robin. The weather.
New York: Marshall Cavendish, 1994. (Let's investigate science)
ISBN 1-85435-630-5 (4-6)

Kramer, Stephen. Eye of the storm: chasing tornadoes with Warren Faidley.
New York: Putnam Pub. Group, 1999.
ISBN 0-399-23029-2 (hc) (2-5)
ISBN 0-698-11766-2 (pbk) (2-5)

Kramer, Stephen. Tornado: nature in action.
Minneapolis, MN: Carolrhoda Books, 1997.
ISBN 1-57505-058-7 (4-6)

Lye, Keith. Temperate climates.
Austin, Tex.: Raintree Steck-Vaughn, 1997.
ISBN 0-81724-827-7 (4-6)

Petty, Kate et Jakki Wood. Le ciel et ses mystéres.
Saint-Lambert, Québec : Héritage, 1994.
ISBN 2-7130-1583-9 (4-6)

Rosado, Maria. Blizzards! And ice storms. 1st ed.
New York: Simon spotlight, 1999. (The Weather channel presents)
ISBN 0-689-82016-X (pbk.) (4-6)

Science in the air. Presented by World Book Encyclopedia.
Chicago, IL: World Book, 1998. (How and why science)
ISBN 0-7166-7111-5 (pbk.) (4-6)

Steele, Philip. Snow and ice.
Austin, TX: Raintree Steck-Vaughn, 1998. (Living with the weather)
ISBN 0-8172-5052-2 (4-6)

Suzuki, David. You are the earth: from dinosaur breath to pizza from dirt.
Vancouver: Greystone Books, 1999.
ISBN 1-55054-751-8 (4-6)

Swanson, Diane. The day of the twelve story wave: grinding glaciers, howling hurricanes, spewing volcanoes, and other awesome forces of nature.
Vancouver; Toronto: Whitecap Books, 1995.
ISBN 1-55110-374-5 (4-6)

Taylor, Barbara. Le temps et le climat.
[adaptation française, Véronique Bussolin]
Bonneuil-les-Eaux, [France]: Gamma; Montréal, Qué: École active, [1997].
(Flash info) ISBN 2-71301-809-9 (Gamma).
ISBN 2-890695484 (École active)

VanCleave, Janice Pratt. Janice VanCleave's weather: mind-boggling experiments you can turn into science fair projects.
New York: John Wiley, 1995. (Spectacular Science Projects)
ISBN 0-471-03231-X (4-6)

Wyatt, Valerie. Weather: frequently asked questions. Illus. by Brian Share.
Toronto: Kids Can Press, 2000.
ISBN 1-55074-582-4 (hc)
ISBN 1-55074-815-7 (pbk.) (3-5)

Wyma, Brenda. Weather. Illus. by Diane Valko.
Cypress, CA: Creative Teaching Press, 1995. (Investigations in science)
ISBN 0-003-48280-2 (4-7)

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Grades 7-12

Gold, Susan Dudley. Blame it on El Niño. Expert review by David Adamec, NASA oceanographer.
Austin, Tex.: Raintree Steck-Vaughn, 2000.
ISBN 0-7398-1376-5 (6-10)

Hodgson, Michael. Weather forecasting. 2nd ed.
Guildford, CT: Globe Pequat Press, 1999. (Basic essentials)
ISBN 0-7627-0478-0 (7-10)

Kahl, Jonathan D. National Audubon Society first field guide. Weather.
New York: Scholastic Press, 1998.
ISBN 0-590-05469-4 (hc)
ISBN 0-590-05488-0 (pbk) (7-12)

Murphree, Tom. Watching weather. Tom Murphree and Mary K. Miller with the Exploratorium.
New York: Henry Holt & Co., 1998. (The accidental scientist)

Sciencepower 10 : science, technology, society, environment.
Toronto: McGraw-Hill Ryerson, 2001.
ISBN 0-07-560363-2 (9-12)

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Adult and Teacher Resources

Abley, Mark. The ice storm : an historic record in photographs of January 1998.
Toronto: McClelland & Stewart, 1998.
ISBN 0-7710-6100-5

Abley, Mark. Stories from the ice storm. (Edited by Mark Abley.)
Toronto: McClelland & Stewart, 1999.
ISBN 0-7710-0653-5 (bound)
ISBN 0-7710-0654-3 (pbk)

Berger, John J. Beating the heat : why and how we must combat global warming.
Berkeley, CA: Berkeley Hills Books, 2000.
ISBN 1-893-16305-9

Bluestein, Howard B. Tornado alley : monster storms of the Great Plains.
New York, N.Y.; Oxford, U.K.: Oxford University Press, 1999.
ISBN 0-19-510552-4

Bowyer, Peter J. Where the wind blows : a guide to marine weather in Atlantic Canada.
(Published in co-operation with Environment Canada).
St. John's, Nfld.: Breakwater Books Ltd., 1995.
ISBN 1550811193

Burroughs, William James. The climate revealed.
Cambridge, U.K.; New York: Cambridge University Press, 1999.
ISBN 0-521-77081-5

Canada. Environment Canada. Ontario Region. Clouds. [wall chart] [Downsview, Ont.]: Environment Canada, Ontario Region, Commercial Services Branch, [1999].
ISBN 0-662-27621-3
Gov't. Cat. No. En56-134 /1999E

Canada. Environnement Canada. Région de l'Ontario. Les nuages. [planche murale]
[Downsview, Ont.]: Environnement Canada, Région de l'Ontario, Direction des services commerciaux, [1999].
ISBN 0-662-83539-5
No. gouv. de cat. No. En56-134 /1999F

DeBlieu, Jan. Wind : how the flow of air has shaped life, myth, and the land.
Boston: Houghton Mifflin, 1998.
ISBN 0-395-78033-0

Dunlop, Storm. A dictionary of weather.
Oxford: Oxford University Press, 2001.
ISBN 0-19-280063-9

Eden, Philip and Clint Twist. Weather facts.
Willowdale, ON: Firefly Books, 1995.
ISBN 1-895565-64-2

Encyclopedia of climate and weather. Ed. by Stephen H. Schneider.
New York; Oxford: Oxford University Press, 1996.
ISBN 0-19-509485-9 (set)

Engelbert, Phillis. The complete weather resource. (4 vol. set)
Detroit, Mich.: UXL, 1997-2000.
ISBN 0-8103-9787-0 (set)

Fleming, James Rodger. Historical perspectives on climate change.
New York; Oxford: Oxford University Press, 1998.
ISBN 0-19-507870-5

Freier, George D. Weather proverbs and quotes.
New York: Random House, 1999.
ISBN 0-517-20194-1

Goldstein, Mel. The complete idiot's guide to weather.
New York: Alpha Books; Distr. by Macmillan, 1999.
ISBN 0-02-862709-1

Graedel, T.E. Atmosphere, climate and change.
ISBN 0-7167-5049-X

Heidorn, Keith. The Weather Doctor's almanac 2000.
Victoria, B.C.: Spectrum Educational Enterprises, 2000.

Old Saybrook, Conn.: Globe Pequot Press, 1999. (Basic essentials)

Kramer, Stephen P. Eye of the storm: chasing storms with Warren Faidley.
Photographs by Warren Faidley.
New York: G.P. Putnam's & Sons, 1997.
ISBN 0-399-23029-7

Lange, Owen S. The wind came all ways: a quest to understand the winds, waves and weather in the Georgia Basin.
Vancouver, B.C.: Environment Canada, Atmospheric Environment Service, 1998.
ISBN 0-660-17517-7.
Gov't Cat. No. En56-74 /1998E.

Lyons, Walter A. The handy weather answer book.
Detroit, MI: Visible Ink Press, 1997.
ISBN 0-7876-1034-8

Monmonier, Mark. Air apparent: how meteorologists learned to map, predict, and dramatize weather.
Chicago; London: University of Chicago Press, 1999.
ISBN 0-226-53422-7

Organisation météorologique mondiale. Une décennie contre les catastrophes.
Genève, Suisse: OMM, 1994. [OMM No. 799]
ISBN 92-63-20799-2

Organisation météorologique mondiale. En première ligne : Les services météorologiques publics.
Genève, Suisse: OMM, 1994. [OMM No. 816]
ISBN 92-63-20816-6

Organisation météorologique mondiale. Météo et sports.
Genève, Suisse: OMM, 1996. [OMM No. 835]
ISBN 92-63-20835-2

Organisation météorologique mondiale. Observer l'environnement de la planète : le temps, le climat, l'eau.
Genève, Suisse: OMM, 1994. [OMM No. 796]
ISBN 92-63-20796-8

Organisation météorologique mondiale. Le temps, le climat et la santé.
Genève, Suisse: OMM, 1999 (OMM No. 892)
ISBN 92-63-20892-1

Phillips, D.W. Blame it on the weather: strange Canadian weather facts.
Toronto, Ont.: Key Porter, 1998.
ISBN 1-55013-968-1

Phillips, D.W. Canadian weather trivia calendar.
Downsview, Ont.: Environment Canada, 2001.

Phillips, D.W. L'Almanach météorologique canadien.
Downsview, Ont.: Environment Canada, 2001.

Pielke, Roger A. Hurricanes: their nature and impacts on society.
Roger A. Pielke , Jr. and Roger A. Pielke, Sr.
New York: John Wiley & Sons, 1997.
ISBN 0-471-97354-8

Pommainville, Pierre. AWARE: aviation weather: playing by the rules.
[Saint-Laurent, Qué]: Environment Canada, Quebec Region, 1996.
ISBN 0-660-16445-0.
Gov't Cat. No. En56-84 /1996E.

Pommainville, Pierre. MÉTAVI : tout sur les règles du jeu en météo aviation.
[Saint-Laurent. Qué.]: Environnement Canada, Région du Québec, 1996.
ISBN 0-660-95253-X. Gov't Cat. No. En56-84 /1996F.

Posey, Carl A. The living earth book of wind & weather.
Pleasantville, NY; Montreal: Readers' Digest Association, Inc., 1994.
ISBN 0-89577-625-1

Reynolds, Ross. Cambridge guide to the weather.
Cambridge; New York: Cambridge University Press, 2000.
ISBN 0-521-77489-6

Rosenfeld, Jeffrey O. Eye of the storm: inside the world's deadliest hurricanes, tornadoes, and blizzards.
New York: Plenum Press, 1999.
ISBN 0-306-46014-9

Sorbjan, Zbigniew. Hands-on meteorology: Stories, theories and simple experiments.
Boston, Mass.: American Meteorological Society, 1996.
ISBN 1-87220-20-9

Soul of the sky: exploring the human side of weather. Edited and compiled by Dave Thurlow and C. Ralph Adler.
North Conway, NH: Mount Washington Observatory, 1999.
ISBN 0-931134-99-4

Stevens, William K. The change in the weather: people, weather, and the science of climate.
New York: Delacorte Press, 1999.
ISBN 0-385-32012-4

Stull, Roland B. Meteorology for scientists and engineers. 2nd ed.
Pacific Grove, CA: Brooks/Cole Thomson Pub., 2000.
ISBN 0-534-37214-7

Verkaik, Arjen. Manuel de l'observateur de temps violent. Éd. Rev.
Elmwood, Ont.: Whirlwind Books, 2000.
ISBN 0-9681537-3-9

Verkaik, Arjen. Severe weather watcher handbook. Rev. ed.
Elmwood, Ont.:Whirlwind Books, 2000.
ISBN 0-968153702-0

Verkaik, Arjen. Le vent, les temps, les vagues : guides des conditions météorologiques maritimes sur les Grands Lacs. (Aussi inclus dans : La trousse d'information sur les conditions météorologiques maritimes sur les Grands Lacs pour la sécurité nautique).
Downsview, Ont; Hamilton, Ont.: Environnement Canada, Région de l'Ontario, 1998.
ISBN 0-660-95936-4.
Gov't Cat. No. En56-125 /2-1998F.

Verkaik, Arjen. Wind, weather & waves: a guide to marine weather in the Great Lakes region. (Also included with: The Great Lakes marine weather kit for safer boating).
Downsview, Ont.; Hamilton, Ont.: Environment Canada, Ontario Region, 1998.
ISBN 0-660-17436-7.
Gov't Cat. No. En56-125 /2-1998E.

Verkaik, Jerrine. Under the whirlwind: everything you need to know about tornadoes but didn't know who to ask.
Elmwood, Ont.: Whirlwind Books, 1997.
ISBN 0-9681537-0-4

Watts, Alan. The weather handbook. 2nd ed.
Dobbs Ferry, NY: Sheridan House, 1999.
ISBN 1-574-09081-X

Wheaton, Elaine. But it's a dry cold: weathering the Canadian Prairies.
ISBN 1-894004-01-9

Williams, Jack. The weather book. 2nd.ed.
New York: Vintage Books; Toronto: Random House of Canada, 1997.
ISBN 0-679776-65-6

World Meteorological Organization. Climate and human health.
Geneva, Switzerland: WMO, 1996. (WMO No. 843)
ISBN 92-63-10843-9

World Meteorological Organization. A Decade against natural disasters.
Geneva, Switzerland: WMO, 1994. [WMO No. 799] ISBN No. 92-63-10799-8

World Meteorological Organization. Observing the world's environment: weather, climate & water.
Geneva, Switzerland: WMO, 1994. [WMO No. 796] ISBN 92-63-10769-3

World Meteorological Organization. On the front line: Public Weather Services.
Geneva, Switzerland: WMO, 1994. (WMO No. 816) ISBN 92-63-10816-1

World Meteorological Organization. Weather and sports.
Geneva, Switzerland: WMO, 1996. (WMO No. 835) ISBN 92-63-10835-8

World Meteorological Organization. Weather, climate and health.
Geneva, Switzerland: WMO, 1999. (WMO No. 892) ISBN 92-63-10892-7

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