CBC channel reported on Sunday that Quebec turned out to be the most affected region, where more than 1,000 people were forced to leave their houses.
Montreal Mayor Denis Coderre declared a state of emergency in the region, set to remain in effect for at least 48 hours.
"If people's lives are in jeopardy, we need to think about the people first," Coderre was quoted as saying by the broadcaster.
The city of Gatineau, local near the country's capital of Ottawa, was also badly affected, with local authorities having evacuated more than 700 people.
The rescue and search operations are underway.