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Canada's Top Ten Weather Stories for 2011

Ontario - Regional Highlights

Record Wet March and High Water Levels

From March 4 to 6, a warm spring storm dropped in excess of 40 mm of rain on the frozen saturated ground across the lower Great Lakes. With the snow-melt already in full swing, the ground could not absorb the infusion of water, creating a high risk of flooding in several low-lying areas from Toronto to Windsor. Ice jams were a concern, especially in southern areas of the Grand River, and on March 5 an 8-year-old girl drowned in the raging waters of Gentleman Creek, a tributary of the Thames River.

Essex-Lambton Tornado

Residents in southwestern Ontario assessed the damage after a tornado-like storm on July 23 tore through Lambton, Elgin and Middlesex counties. Near Petrolia, a barn collapsed, trapping about 100 chickens. Hydro One said the storm toppled eight steel transmission towers in east Lambton, cutting power to 13,000 customers. The wind event included downburst winds and an F2 tornado with winds of 200 to 230 km/h. On a positive note, the storms brought much-needed rain to areas that had been drying out through the month.

Four Tornadoes in One Day

On August 16, a line of powerful thunderstorms triggered by a cold front ripped through northwestern Ontario including Kenora, Grassy Narrows, Ear Falls, Vermillion, and Dryden. An aerial survey combined with some first-hand accounts confirmed that four separate tornadoes occurred. Two were in the Ear Falls area, one was west of Dryden, and still another was northwest of Sioux Lookout. All four tornadoes were rated as F1 events, with peak winds between 120 and 170 km/h. Damage was mostly confined to downed trees.

Windsor Sets Annual Precipitation Record

On October 19, Windsor easily set its all-time record for the wettest year ever when 55.4 mm of rain poured down on the city, making the year-to-date total precipitation 1,265 mm. This broke the previous full-year record of 1,227.5 mm set in 1990 and was well over the average yearly total of 918 mm. Windsor experienced precipitation on almost 60 per cent of days in 2011. Many of the numerous weather systems passing through the area were unusually slow-moving or stalled, having more time to dump their contents. By December 1, Windsor had recorded 1,477 mm of rain and melted snow, compared to a normal precipitation total for the first 11 months of 844 mm. That included nine months with over 100 mm, five with over 150 and one with over 228 mm (September). In May, the city began offering a basement-flooding subsidy for homeowners who installed backwater valves and new sump pumps.

Could Have Been Snow

A moisture-laden low-pressure system that originated over the southeastern U.S. moved across Ontario and into southern Quebec on November 29. Residents from Windsor to Gatineau sloshed through 50 to 80 mm of rain, and provincial conservation authorities warned people to stay away from water. Several localities established new record rainfall amounts, with areas around southwestern Ontario getting the most rain. The city of Windsor handled nearly 350 calls relating to flooding issues, while freezing rain in parts of central and northern Ontario led to school bus cancellations in many districts. About 30,000 Hydro One customers from Gravenhurst to north of Huntsville and around Collingwood were left without power.

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