Severe thunderstorm downs trees, floods roads across Toronto

A severe thunderstorm pounded Toronto on Tuesday afternoon, leaving behind downed trees and wires, flooded roads and basements and some elevators stalled due to power outages.

A severe thunderstorm warning ended shortly before 7 p.m., a rainfall warning ended at 8:15 p.m., and a severe thunderstorm watch ended by 10:40 p.m. A heat warning ended overnight Tuesday. 

Environment Canada said conditions were favourable for the development of "dangerous thunderstorms" that could produce strong winds, with gusts of up to 90 to 110 kilometres per hour, and torrential rain, with amounts nearing 50 millimetres.

An earlier thunderstorm brought torrential rain, coin-sized hail and strong winds to Toronto. In a few areas, wind gusts brought down trees, pulling down wires and leaving damaged cars in their wake.

Doug Harper, a platoon chief with Toronto Fire Services, said they received more than 130 calls for help on Tuesday afternoon over the course of about two hours and 40 minutes. Residents called about downed trees and wires, stalled elevators and flooded basements.

"It's been very hectic but nothing out of the ordinary during a storm event," Harper said.

Const. David Hopkinson, a spokesperson for the Toronto Police Service, said police received reports of flooded roadways, but he said the flooding was not significant.

"It's nothing out of the ordinary," Hopkinson said.

Environment Canada issued the rainfall warning hours after the heat warning came into effect on Tuesday, warning of rainfall amounts of 25 millimetres in some areas.

'Localized flooding'

"Heavy downpours can cause flash floods and water pooling on roads," Environment Canada warned.

"Localized flooding in low-lying areas is possible. Heavy rainfall in combination with other weather factors, such as hail, wind and lightning, will make outdoor activities unsafe."

Earlier, the federal weather agency said warm and humid conditions were forecast to continue in the city until Tuesday night.

Environment Canada said the humidex would make it feel in the mid to upper 30s on Tuesday evening. The low on Tuesday night was forecast to be likely closer to 20 C.

The forecast calls for cooler temperatures and lower humidity on Wednesday.

Environment Canada said humidity can cause the air quality health index to approach the high risk category.

"Extreme heat affects everyone," Environment Canada said in its heat warning.

It noted that the risks are greater for young children, pregnant women, older adults, people with chronic illnesses and people working or exercising outdoors.

Signs of heat illness include swelling, rash, cramps, fainting, heat exhaustion, heat stroke and the worsening of some health conditions.

"Never leave people or pets inside a parked vehicle," the federal agency added.

Rivers in GTA could have higher flows, water levels

The Toronto and Region Conservation Authority (TRCA), in a flood outlook for the city in effect until Wednesday, said all rivers in the GTA could experience higher flows and water levels due to Tuesday's storms.

"The combination of slippery and unstable banks, and rising water levels could create hazardous conditions close to any river, stream or other water bodies," the TRCA says. "Some flooding and ponding may occur in low-lying areas or areas with poor drainage, if higher rainfall amounts materialize with multiple thunderstorms over the same area."

Residents are urged to stay away from rivers, streams and shoreline areas and to avoid flooded areas or areas that are eroding.

The storm caused scattered outages in Toronto in the afternoon and evening. Stormy weather in southern Ontario, meanwhile, caused tens of thousands of customers to lose power. 

In a tweet on Tuesday night, Hydro One said: "Crews continue to respond as quickly and safely as possible to a significant number of outages caused by today's severe weather. Customers in the hardest hit areas will be without power overnight. We appreciate your patience."

As of Wednesday morning, the electricity company said it was still dealing with 1,200 outages across southern Ontario.