Power lines have been downed and houses washed into the sea after Storm Fiona battered Canada's coastline.
At least one person died after being washed out to sea in Newfoundland, officials said.
Fiona was downgraded from a hurricane to a tropical storm on Friday. Such weather events are rare in Canada, and police said the storm was "like nothing we've ever seen".
The army has been deployed to Nova Scotia to assist the clean-up.
Parts of five provinces experienced torrential rain and winds of up to 160km/h (100mph), with widespread flooding and hundreds of thousands of people left without power.
Prime Minister Trudeau says the military will be deployed to Nova Scotia, adding: "If there is anything the federal government can do to help, we will be there."
He has said he will no longer travel to Japan to attend the funeral of former Prime Minister Shinzo Abe to deal with the storm's aftermath.
Mr Trudeau convened a meeting of the Incident Response Group on Sunday - the second to discuss Fiona - and promised to "ensure that all necessary support is available" to restore services as quickly as possible.
A 73-year-old woman died when the storm hit Port aux Basques, a small town on the southwest tip of Newfoundland that was one of the hardest hit areas.
"The woman was last seen inside [her] residence just moments before a wave struck the home, tearing away a portion of the basement," the police said. The coast guard and rescuers recovered her body from the sea on Sunday.
Port aux Basques is "like a complete war zone," with more than 20 homes destroyed and 200 people displaced, said mayor Brian Button. He added that damages were in the millions of dollars.
Rosalyn Roy, a local resident, told the Canadian Broadcasting Corp that rebuilding would take "months".
Earlier, a woman was rescued after being "tossed into the water as her home collapsed".
Government officials have said the country's military will be deployed to help clear trees and roads.
A police chief on Prince Edward Island urged residents to stay inside "unless absolutely necessary" as recovery efforts continued.
Power companies have warned that it could take days to restore electricity, as wind speeds remain too high to start work on downed power lines. Severe hurricanes in Canada are rare, as storms normally lose their energy once they hit colder waters in the north and become post-tropical instead.
Fiona had already wreaked havoc on Puerto Rico and the Dominican Republic earlier this week, with many still left without power or running water.
Florida also faces a hurricane threat as tropical storm Ian strengthened as it moved over the Caribbean on Saturday. It could approach Florida early next week as a major hurricane.