A severe thunderstorm forced the shutdown of Toronto's subways, cut power to 300,000 in Canada's largest city and caused Porter Airlines to cancel all flights out of the downtown airport Monday evening.
Environment Canada said some parts of the city had been drenched with more than 3.5 inches (90 millimeters) of rain in the evening storm, easily beating the previous one-day rainfall record of 1.4 inches (29.2 mm) in 2008.
Downtown was dotted with abandoned vehicles, some sitting in water up to their windows. Some subway stations were flooded. Partial subway service later resumed, but large parts of the system were still shut down Monday night.
Some commuter overland trains were disrupted during rush hour after tracks were submerged. Metrolinx spokeswoman Vanessa Thomas said the police marine rescue unit had started to evacuate passengers from one train with water up to its windows.
"There's a full-on river on either side of us... We. Are. Stuck. Hard," passenger Jonah Cait quipped on Twitter.
It was not clear how many flights were affected when the Porter Airlines terminal at the downtown airport lost power and the North American airline cancelled all of its flights.
Hydro Toronto spokeswoman Tanya Bruckmueller said efforts to resume power to customers might be slowed as night fell.
Toronto's flash flooding comes two weeks after extensive flooding in Calgary turned parts of the western Canadian city into a lake and forced up to 100,000 Albertans from their homes. Three bodies were recovered during the floods.