Lightning Information

Every thunderstorm produces lightning. By tracking the lightning strokes, forecasters can tell where thunderstorms are active, even in areas without weather stations or radar coverage.

Lightning over Lake Erie.
Lightning over Lake Erie.
© Environment Canada
Photo: Bruce Harrison

The turbulence within cumulonimbus or thunderstorm clouds creates electrically charged areas within the clouds--sometimes positively charged and sometimes negatively charged. When the charge builds up enough, it will cause an electrical spark to jump from one cloud to another or from the cloud to the ground or vice versa.

Sample of lightning data on a forecaster's workstation

The little clip on the right is a sample of how lightning information is displayed on a forecaster's workstation. This one shows thunderstorm activity between Flin Flon and The Pas, Manitoba, on an August afternoon. Each plus or minus sign represents a stroke of lightning, and the display is colour-coded to show how many minutes old each stroke is, with the red being the most recent. That way, forecasters can monitor the movement of thunderstorm cells. Positive lightning strokes are shown as a plus sign and negative ones, as a minus sign. Forecasters have found that positive strokes are less common but are more likely to be associated with severe weather damage.

Lightning map on Environment Canada's Web site

The picture on the left shows how lightning data is presented on our public Web site. To see if there's any lightning in your neighbourhood today, have a look at our Web page. You can learn more more about the Canadian Lightning Detection Network by following this link from our Network Compound, and you can learn more about lightning in Canada by visiting our new Lightning website.

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