Severe thunderstorm warnings are in effect for parts of the province as two storm clusters make their way through southern Ontario.

Severe thunderstorms cause major flooding, traffic nightmare in southern Ontario

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Tuesday, July 9, 2013, 7:24 AM -

SEVERE STORMS IN SOUTHERN ONTARIO: Tune into The Weather Network on TV for ongoing updates.

Localized flooding, dark skies and heavy rain across southern Ontario, prompted Environment Canada to issue severe thunderstorm warnings that stretched from the Greater Toronto Area up to southern Grey County Monday.

Flooding and intense lightning were reported in a number of communities.

As of 10 p.m., Toronto Pearson reported 123 mm of rain, making it Toronto's rainiest day ever, unofficially.

There have been several reports of small sinkholes opening up in the city.

MAJOR POWER OUTAGES

According to Toronto Hydro, approximately 6,000 customers are without power in Etobicoke, and about 80% of Mississauga is in the dark. In Markham and Richmond Hill, 29,000 customers lost their electricity but by the evening, power had been restored to most Markham residents.

About 300,000 people were without power in total.

Hydro spokeswoman Tanya Bruckmueller said repair efforts might be further dragged out by the onset of nightfall.

"There's not a lot that will change once it starts getting dark. It'll be harder for the crews... they need to be able to identify where the damage is so it'll take longer in the night."

TRAFFIC NIGHTMARE

The Toronto Transit Commission stopped all subways at the height of rush hour due to signal and power issues throughout the city, leaving scores of commuters stranded in office buildings and along subway platforms.

Go train tracks were submerged with water, grinding trains to a halt. A section of track on the Lakeshore West line west of Long Branch is said to be washed out.

Twitter user @juliakristine_ posted a dramatic photo of ankle-deep water taken inside a GO train car on the Richmond Hill line. Another image, taken at Bayview at Pottery, shows a partially-submerged train with smashed windows. Desperate commuters climbed through them and waded through waist deep water in an attempt to get home.

Toronto's Marine Unit was deployed to rescue the passengers.

@weathernetwork Its getting darker and we've had to break open many windows and doors to allow the passengers to breath. — JULIA♡ (@juliakristine_) July 9, 2013

RT @juliakristine_ People who've jumped out of the train are apparently hanging onto trees, so as not to be overtaken by the current. — The Weather Network (@weathernetwork) July 9, 2013

Traffic along major roadways is no better: a major artery the Don Valley Parkway was partly closed as the Toronto Region Conservation Authority said the Don River's banks were at risk of collapse, while provincial police warned drivers to steer clear of parts of Highways 427, 401 and 27, all due to flooding. Porter Airlines has cancelled all flights at Billy Bishop Airport.

Water from flash flooding poured out of sewer drains while Toronto's downtown core was dotted with abandoned vehicles, some sitting in water up to their windows. One woman, sporting a T-shirt and shorts, dove head-first through the window of her marooned car before wading away in the thigh-deep water.

Noëlle Lombardi was stuck under a Toronto overpass for more than an hour when the flash floods hit.

"People's cars are stuck in the water," she said, adding that it was about ankle-deep.

"I've been trying to maneuver my way through this weather and it's just not happening."

Commuters are being advised that public transportation disruptions may continue into Tuesday.

Temperatures dropped rapidly along with the storm. In Mississauga, for example, temperatures went from 28C to 22C in an hour.

Toronto Mayor Rob Ford advised residents to stay home unless absolutely necessary. For those stuck on the road, Toronto and Region Conservation Management are urging drivers to exercise extreme caution and avoid driving through low lying areas and roadways.

Check our traffic cameras for a live look at the drive and where any potential back ups may occur. Also, check the traffic flow map for real-time updates on the roads.









With files from the Canadian Press