Several parts of Ontario are under a tornado watch while many other communities are under a severe thunderstorm watch as high temperatures grip much of the province.
Environment Canada has issued tornado watches for regions that include Barrie, Grey-Bruce, Algonquin, London, Waterloo and Windsor.
The weather agency also says severe thunderstorm watches are in effect for much of northern and southern Ontario, including the Greater Toronto Area.
Many parts of the province remain under a second day of heat warnings, with temperatures expected to reach or surpass 30 C and hit the upper thirties when combined with humidity.
Environment Canada is warning residents to be prepared for severe weather and take cover immediately if threatening weather approaches.
In the event of a tornado, it advises going indoors to a lower floor and away from windows and outside walls.
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