High winds gusting up to 120 km/h swept through southern and eastern Ontario, then pounded Quebec on Thursday, killing at least one person, injuring a dozen, capsizing boats and knocking out power to about 300,000 homes.

Environment Canada issued a wind warning just before 11 a.m., with high winds hitting the Niagara Region through Hamilton, Toronto and the north shore of Lake Ontario into Prince Edward County.

Violent winds were blamed for a death in Grimsby, Ont., about 30 kilometres east of Hamilton. Niagara Regional Police said a man in his 70s was killed when he was struck by a flying garage door, which had been leaning against a shed before the wind lifted it up. The man lived on the property.

At least a dozen other people were reported hurt in Ontario and Quebec.

The Burlington Skyway bridge and Garden City bridge in St. Catharines were closed for a few hours because of the winds. Both were reopened later in the day.

In Hamilton harbour, about five boats full of student rowers were rescued after at least seven boats capsized.

The wind warning ended at about 1 p.m.

Power outages hit 150,000 Ont. homes

Hydro crews were working to restore power to 150,000 homes across the province, said Nancy Shaddick of Hydro One.

"Depending on the situation, power can be restored quickly or rerouted to bring power back to a lot of the community," she said.

About 20,000 lost power in Ottawa, which also felt the winds, and Ottawa Hydro said it would switch to a backup distribution system to restore electricity as soon as possible.

Horizon Utilities said some 30,000 of its customers were without power in St. Catharines, along with about 6,500 in Hamilton.

"Winds have knocked down poles and knocked down wires as well as trees falling on wires," said Tony Iavarone, the utility's spokesman. "It's died down now in Hamilton, but in St. Catharines we still see more occurring."

Students at Lockview Public School in St. Catharines were forced to leave the building after gusting winds tore off part of the school's roof. No injuries were reported.

Overturned trucks and debris caused delays on the Queen Elizabeth Way through the Niagara Region.

Garbage pickup was put on hold in the area and landfills were closed.

Police were warning drivers to use caution and urged everyone to be careful after reports of downed power lines and trees.

High winds toppled this parking sign in downtown Toronto on Thursday. (Jamie Strashin/CBC News)

In Toronto, waves up to three metres high were spotted on the lakeshore and the Boulevard Club, located on the lake directly south of Roncesvalles Avenue, had to close because of flooding caused by high waves.

The club's docks also suffered damage from high waves.

Toronto fire crews were busy responding to calls about downed power lines and Twitter users were calling Toronto "the windy city" in messages posted on Thursday morning.

Wind warning issued for much of Quebec

Environment Canada also issued a wind warning for much of Quebec on Thursday, warning of wind gusts up to 90 km/h.

The winds knocked out power to at least 155,000 customers in the province in the afternoon.

Outages were reported in the Outaouais, on the South Shore, in Laval, the Laurentians, the Eastern Townships and Central Quebec.

With files from The Canadian Press