Environment Canada has issued tornado watches for parts of the Greater Toronto Area on Thursday night.
The areas are all north of Toronto.
As of about 9:50 p.m., the federal weather agency said the watches apply to Caledon in Peel Region, as well as Newmarket and Georgina in northern York Region and Uxbridge and Beaverton in northern Durham Region.
Environment Canada said conditions are favourable for the development of severe thunderstorms that may produce tornadoes. The weather could also bring strong winds, large hail and heavy rain.
Severe thunderstorms will continue to sweep through these regions on Thursday night, the agency added.
Wind gusts of up to 110 kilometre per hour and nickel to toonie sized hail are potential hazards.
“This is a dangerous and potentially life-threatening situation. Be prepared for severe weather. Take cover immediately, if threatening weather approaches,” the federal weather agency said.