TORONTO (Reuters) - A heavy rainstorm in Toronto caused power outages and transit chaos across Canada's largest city on Monday, with flooding shutting down parts of its subway and major roads.

Toronto Hydro, the main electrical utility, said some 300,000 customers lost power after the sudden storm, which dumped more than 90 millimeters (3.5 inches) of water on parts of the city.

The rain also flooded subway stations, closing down large parts of three subway lines, the city's public transit operator said. Many streetcars and buses in the downtown area were forced to stop or divert.

Photos shared via social media showed some drivers abandoning vehicles as the water in underpasses and low spots rose up to their windows.

(Reporting by Jeffrey Hodgson; Editing by Eric Walsh)