Communities across Quebec began assessing the damage on Saturday after remnants of Hurricane Debbie caused power outages for hundreds of residents and struck several parts of the province with record rainfall.

The historic deluge that brought over 140 mm of rain to Montreal Island washed out roads and flooded basements across Quebec. The regional police in the Mauricie region said they are now searching for an 80-year-old pedestrian who they fear may have been swept away by the Batiscan River late Friday after a nearby road collapsed.

Emergency services were called to the scene in the municipality of Notre-Dame-de-Montauban around 11:30 p.m., but the area is currently inaccessible and dangerous, making it difficult for police to conduct their search.

Police spokesperson Camille Savoy said, "Since it is impossible for police officers to search along the banks of the river, drones are being used to detect any item that could help us locate the missing person."

Canadian Environment meteorologist Gregory Yang said the worst of the storm is over, with remnants currently remaining over Anticosti Island in the Côte-Nord region of the province and moving eastward. Rainfall amounts between 10 and 15 mm are expected.

Yang described the rainfall as historic, not only for Montreal but likely for neighboring areas such as the Laurentians.

He stated, "It's extremely significant."

The rain inundated the western tip of Montreal Island with up to 173 mm on Friday, while 145 mm fell on the downtown area. Both totals shattered the previous one-day record of 102.8 mm set in the Montreal area in November 1996. The rainfall on Friday also exceeded the entire average rainfall for the month of August, which is 94.1 mm.

However, other parts of the province experienced higher levels of rainfall. The municipality of Lanoraie in the Lanaudière region recorded 221 mm.

The Quebec Ministry of Transportation issued a statement on Saturday saying the storm caused severe damage to many roads, with the Lanaudière and Mauricie regions being the most affected.

A statement from the City of Ottawa also noted that some roads in the West Carleton and Kanata neighborhoods were severely damaged.

The storm plunged hundreds of thousands of Quebec residents into darkness, and work is still ongoing to restore power. More than 70,000 customers were without electricity as of 2 p.m. on Saturday, down from about 550,000 customers affected on Friday evening.

Outside Quebec, Fredericton received 57.8 mm of rain as the storm moved eastward into New Brunswick, with more rain expected. Yang said the city could expect some rain on Saturday afternoon, but nothing dramatic like what Quebec experienced.

Many municipalities in Ontario also had their share of rain during Friday's storm. The city of Somerset recorded 117.9 mm of rain, while Kenburn, Cornwall, and Ottawa saw 115.8, 95, and 74.7 mm respectively.