The town of Rigaud, Que., has declared a state of emergency and ordered the evacuation of some 150 homes in an area at risk of being flooded by both the Rigaud and Ottawa rivers.
Officials say some 60 residences are already flooded and the 150 homes under the evacuation order are accessible by a single road, which it's feared could be submerged Thursday night.
Rigaud Mayor Hans Gruenwald says if that route is flooded, the town near the Ontario border won't be able to provide services for residents in the event of an emergency.
Heavy rain and spring runoff have also caused some overflowing on roads in other areas in Quebec, including sections of Laval north of Montreal.
The Gatineau, Outaouais and Milles-Iles rivers along with Riviere des Prairies also have high water levels and the rain forecast through Thursday night could cause them to overflow their banks.
In Mandeville, northeast of Montreal, several hundred homes have been isolated by flooding from the Mastigouche River, but no evacuation has yet been ordered.