Thunderstorm also causes severe flooding and forces flight cancellations at Pearson airport.

A powerful thunderstorm has hit Canada’s largest city, Toronto, damaging buildings, closing roads and cutting power to tens of thousands of residents.

The storm on Wednesday brought torrential rain, strong winds, and large hail, prompting tornado watches and warnings in some areas.

At least 45,000 customers were without electricity as of 8pm on Wednesday (00:00 GMT on Thursday), according to electricity provider Toronto Hydro.

The storm brought down trees and caused flooding, prompting road closures in the city, including on the Don Valley Parkway, the CBC reported.

The Michael Garron Hospital, located in Toronto’s East York community, said its emergency department has been affected by flooding.

Images published by the CBC showed cars nearly submerged in the city of Vaughan, north of Toronto.

Toronto Mayor Olivia Chow said in a post on X that the city’s emergency operations centre has been activated since Wednesday morning.

“City crews are already out responding to downed power wires, fallen trees, flooding and more,” she said. The Toronto Transit Commission, which operates subways and buses, “is working to restore service where it has been affected by flooding and debris spread by high winds”, she added.

Dozens of flights set to depart Toronto Pearson International airport on Wednesday evening were either delayed or cancelled.

Canada’s weather agency, Environment and Climate Change Canada, lifted an orange warning for severe thunderstorms in the Greater Toronto Area.

But a yellow alert warning of heat and severe thunderstorms remained in place over parts of the southwestern Ontario province.