After weeks of unusually high rainfall saturated the Greater Toronto Area, Hazel dropped additional rainfall, peaking at 8.4 in (214 mm) in Snelgrove, Ontario. In three hours, the city received 3.5 in (90 mm) of precipitation. Most of these rains ran off into rivers and creeks of Toronto, which raised water levels by as much as 20–26 ft (6–8 m).[6][16] Not built to withstand heavy flooding, Toronto’s infrastructure took a heavy hit: over 50 bridges, many parts of important highways, as well as numerous roads and railways were destroyed when the high water washed them out or carried debris and smashed them.
from Wikipedia below,
Hazel, the deadliest and costliest storm of the 1954 Atlantic hurricane season, reached Toronto, Ontario by the evening of October 15, 1954. It peaked as a category 4 storm, but by the time it reached Canada, it was an extratropical category 1 storm after merging with an existing cold front south of Ontario.
