4 people dead in southern Ontario as dangerous thunderstorms roll through

A series of dangerous thunderstorms rolled across southern Ontario on Saturday leaving four people dead.

According to Ontario Provincial Police, one person died and two others were injured after a tree fell on their camping trailer in Brant County.

Police say they were called to the area just before 12:30 p.m.

Emergency crews found three injured people, who were all transported to hospital. One person was pronounced dead at the hospital, while the others were treated for minor injuries.

Police have not released the name of the person who died.

Meanwhile, a woman in her 70s died after being hit by a tree during the thunderstorm, Peel Regional Police said.

Police say the woman was struck just after 1:30 p.m. in the area of Belmont Drive and Birchbank Road in Brampton.

"A large tree struck a woman who was out walking during the storm," police posted on Twitter.

A spokesperson with Peel police told CBC News that the woman was reportedly walking between two houses when the tree fell on top of her.

Emergency crews managed to get her out from under the tree and transported her to hospital, where she died.

In Ottawa, one person died in the city's west end, police said at a Saturday evening press conference.

And Ontario Provincial Police said they were investigating after a 44-year-old man was struck and killed by a falling tree at a cottage near Calabogie, Ont.

In neighbouring Quebec — which had also been under a tornado watch in many regions — Gatineau police told Radio-Canada that a 51-year-old woman died from drowning after a boat capsized in the Ottawa River.

Meanwhile, Toronto police initially told CBC News they received a call that a boat carrying between 15 and 20 people capsized during the storm.

Police later clarified that they were called to the Humber Bay Shores West area for reports of a sailboat with people on board trying to make it back to the shoreline.

The police marine unit responded, along with firefighters and paramedics, but police say they were unable to locate any stranded or capsized boat or vessel.

Police say there were no signs of anyone in distress.

The marine units will continue to patrol the waters to ensure everyone's safety, police wrote in an email to CBC News.

Several cities and towns were under a thunderstorm warning as severe storms rolled across Toronto and most of southern Ontario on Saturday afternoon.

At the peak of the storm, Environment Canada said wind gusts of up to 100 km/h and toonie-sized hail were possible in some places.

"This is a dangerous and potentially life-threatening situation. Large hail can damage property and cause injury," Environment Canada said in a statement. 

"Widespread and extremely strong wind gusts can destroy buildings with tornado-like damage, flatten large stands of trees and blow vehicles off the road." 

Locations impacted by the thunderstorms include:

• Hamilton
• Toronto
• Milton
• Burlington
• Brampton
• Oakville
• Mississauga
• Vaughan
• Richmond Hill
• Markham
• Erin
• London
• Halton Hills
• Ancaster
• Dundas
• Waterdown
• Caledon
• Kitchener-Waterloo
• King City
• Aurora
• Ottawa
• Rockwood
• Stratford

A weather alert was sent to the mobile phones of Ontarians ahead of the storms.

In the alert, Environment Canada warning residents to "take cover immediately if threatening weather approaches."

As of Saturday evening, there were no reports of tornadoes by Environment Canada.

Thousands of customers in Mississauga were without power Saturday afternoon due to the storm, Alectra Utilities said.

Hydro One was also responding to outages caused by the thunderstorms moving across southwestern Ontario.

The company said it was trying to restore power as quickly as possible. In a tweet late Saturday evening, it said it could take "several days" for some to get their power back.

"If you spot a fallen power line or pole, keep at least 10 metres back, even if it doesn't appear to be live. Report it to the police and on our app," Toronto Hydro said in a tweet.