The tropical storm remnant of Hurricane Hazel caused 81 deaths in October 1954 due to flooding that swept homes along river banks into Lake Ontario . A sudden downburst during a strong thunderstorm was believed to have played a contributing factor in the Air France Flight 358 crash in August 2005 . Just a few weeks later , record-breaking intense rainfall , the worst since Hazel , deluged north-central sections of the city within a couple of hours resulting in record insurance claims . Some rain gauges recorded 175 mm ( 7 " ) of rain , over 100 mm ( 4 " ) in just one hour . Another large rainstorm with intense , record rainfall amounts struck a wide swath of the city during the afternoon rush hour on July 8 , 2013 flooding city streets , subway tunnels , basements and knocking out power for over 2 million residents , stranding commuters , some having to be rescued from a submerged train . A daily rainfall record of 126.4 mm ( 5 " ) was set at Pearson Airport , most falling in an hour and a half . Flood insurance claims are likely to exceed the 2005 storm due to a wider area affected
Air France Flight 358
Air France Flight 358
Geography of Toronto