Dorian, now a post-tropical cyclone, is expected to move over or near the Canadian province of Newfoundland and Labrador Sunday and then enter the North Atlantic.
The storm hit Canada's Atlantic coast Saturday with heavy wind and rains that toppled a construction crane into the side of an apartment building under construction in Halifax, the provincial capital of Nova Scotia.
Nova Scotia Power told the Associated Press that 300,000 customers of Halifax, which has a population of 400,000, were without power late Saturday.
Before reaching Canada, Dorian moved over extreme southeastern Massachusetts and Maine in the U.S.
On Friday, Dorian made landfall over Cape Hatteras, North Carolina, after weakening into a Category 1 storm. It generated tornadoes, severe storm surges and flooding in coastal areas in North and South Carolina.
Steve Harris, a resident of North Carolina's Ocracoke Island said, "We went from almost no water to 4 to 6 feet in a matter of minutes."
Dorian was a Category 5 storm when it hit the Bahamas, creating a path of death and destruction, leaving an estimated 70,000 people in need of immediate humanitarian relief.
The official Bahamian death toll is 43, but officials say that will rise, because hundreds, perhaps thousands are missing.
The death toll will be "catastrophic and devastating," Prime Minister Hubert Minnis said, while Health Minister Duane Sands said the final toll "will be staggering."
The U.N. World Food Program warned Saturday that thousands of displaced people are living in "rapidly deteriorating" conditions in the worst-hit parts of the Bahamas in Dorian's aftermath.
"The needs remain enormous," WFP spokesman Herve Verhoosel said in an email Saturday.
"People have no food. People have no water, and it's not right. They should have been gone," Chamika Durosier told the French news agency AFP Saturday as she waited for a flight out of Abaco, one of the most badly damaged areas in the Bahamas. "The home that we were in fell on us," she said. "We had to crawl - get out crawling. By the grace of God, we are still alive."
"Our relief operation is growing, but we are also facing serious challenges in terms of delivering aid," Red Cross spokeswoman Jennifer Eli told Reuters. "Even search-and-rescue choppers haven't been able to reach some people because there's no place to land. These challenges are affecting everyone."