Two people have died and tens of thousands were left without power as a result of stormy weather that swept across northern and central Ontario late Monday night, felling trees and power lines.

Louise Clayton, 42, of Guelph died while camping near Peterborough when a tree fell on her tent trailer around midnight, police said.

A woman is silhouetted against the windows of a grocery store as she buys food in Mattawa, Ont., approximately 65 kilometres east of North Bay, Ont.
(Adrian Wyld/Canadian Press)

Ontario Provincial Police said a second person was killed and another injured near the town of Kiosk at the north end of Algonquin Park. Police said the death was a result of the storm, but did not release any details.

Hydro One reported 170,000 customers were left without hydro Tuesday morning. All customers on Manitoulin Island, about 9,500, were without power, said a spokesman for the utility.

Some customers can expect to be without power for up to 75 hours.

Lighthouse, radio towers knocked down

In North Bay, the storm hit after 5 p.m., knocking out electricity for 90 per cent of customers in the area.

The weather also destroyed a historic lighthouse and knocked over two radio towers in a small town south of North Bay.

Strong winds knocked down hundreds of trees and lightning damaged hydro lines and poles across the province.

A major route in the northeast south of Sudbury, Highway 69, was closed as hydro crews tried to remove downed power lines.

There were reports of possible tornadoes, but the sightings have not yet been confirmed by Environment Canada.

The brief storm prompted states of emergency to be declared in the communities of Mattawa and Callander.

Thousands left without power in GTA, Ottawa

In the Greater Toronto Area, thousands of customers were left without power after sudden, violent winds blew through. Environment Canada said temperatures dropped seven degrees within an hour just after 10 p.m. ET.

More than 50 crews spent Tuesday working on power lines and transformers across the city. Toronto Hydro expected most people to have power returned by early evening.

In the Ottawa Valley, about 3,500 homes lost power, and police and fire crews responded to hundreds of calls of downed trees and power lines.