Tornado warnings issued across Ontario and Quebec, twisters potentially detected by radar

Weather alerts lifted for Ontario and Quebec A spring storm brought heavy winds, hail and a downpour of rain to several communities in Ont. and Que.

Several tornado warnings were issued in Ontario and Quebec amid severe thunderstorms.

"This is a dangerous and potentially life-threatening situation," read a warning from Environment Canada. "If you hear a roaring sound or see a funnel cloud, swirling debris near the ground, flying debris, or any threatening weather approaching, take shelter immediately."

By Thursday night, the last tornado warning had lifted, while 29 areas in Quebec and Ontario were under tornado watches. Power outages, downed trees and damage have been reported.

Latest updates as of 9:50 p.m. ET:

"These severe thunderstorms are embedded in a line of thunderstorms sweeping through the region that are producing nickel to ping pong ball sized hail and 100 km/h wind gusts," Environment Canada warned. "Take cover immediately, if threatening weather approaches."

Tornados and severe thunderstorms are possible in highly populated areas across Ontario and Quebec, including the regions surrounding Toronto, Ottawa and Montreal. Environment Canada issued a cascade of more than 100 severe weather alerts on Thursday, including several tornado warnings.

The department notes that in the case of tornados and thunderstorms, alerts can appear or intensify quickly, sometimes with less than half an hour's notice. Residents are advised to monitor severe weather alerts for their area on Environment Canada's website.

Tornado watch alerts

On Thursday, tornado watches spanned a huge swath of Ontario, including communities like Timmins, Bancroft, Barrie, Collingwood, Midland, Orillia, Haliburton, Bracebridge, Gravenhurst, Huntsville and Peterborough.

In Quebec, tornado watches also extended across Rouy, Val d'Or, Dorval Lodge, Témiscaming, Ville-Marie and Papineauville.

Developing local coverage:

The federal government alert notes that severe thunderstorms are liable to bring tornados, and goes on to advise against water-related activities due to the risk of "violent and sudden gusts of wind," as well as lightning strikes.

Residents in affected areas are advised to go to their basement or lowest floor of their home, away from external walls and windows. Temporary, freestanding shelter such as tents, mobile homes or vehicles should be avoided, in favour of sturdier structures. As a last resort, those without immediate access to shelter should lie in a low spot and protect their head from flying debris.

Severe weather warnings

On Thursday, there were severe weather warnings in Ontario regions such as Elliot Lake, Sault Ste. Marie, Timmins and Kirkland Lake, as well as areas in Quebec like La Sarre.

Warnings describe severe thunderstorms with hail up to the size of a ping pong ball and wind gusts of 90 km/h, as well as a risk of tornados.

"Lightning kills and injures Canadians every year," the warning reads. "Remember, when thunder roars, go indoors!"

Severe thunderstorm watch alerts

Regions and communities that were under severe thunderstorm watches on Thursday included Sudbury, Tobermory, Owen Sound, North Bay, Parry Sound and Timmins in Ontario, and Matagami, Desmaraisville and Mont-Tremblant in Quebec.

Among the potential impacts as storms spread throughout the vast swath of eastern Canada were hot and humid temperatures as high as 33 C, with possible wind gusts of up to 110 km/h and hail up to a golf ball in size.

What to expect

At present, major cities including Toronto, Ottawa, Montreal and Quebec City remain just outside the boundaries of alerts, though CTV Your Morning meteorologist Kelsey McEwen notes that risk of severe storms could extend beyond their current area.

Storms are expected to be intermittent as they move through the Great Lakes region, and may affect Toronto and Montreal later in the day, though with comparatively less risk. They may reach Atlantic Canada by Friday, McEwen notes.