The storm that already walloped the Virgin Islands, Bahamas and North Carolina lashed at far-eastern Canada with hurricane-force winds, knocking out power to hundreds of thousands of people before beginning to weaken late in the day.
Dorian hit near the city of Halifax, ripping roofs off apartment buildings, toppling a huge construction crane and uprooting trees.
There were no reported deaths in Canada, though the storm was blamed for at least 50 elsewhere along its path.
The US National Hurricane Centre said the post-tropical cyclone was centred about 65 miles west-southwest of St Anthony, Newfoundland, in late afternoon.
Its top sustained winds had slipped to 65mph, below the 74mph threshold of hurricane force.
It was heading to the northeast, roughly up the St Lawrence River, at 23mph.
The track was taking take the storm near or over northwestern Newfoundland or eastern Labrador and then out over the North Atlantic by evening.
Nova Scotia officials asked people in the province to stay off the roads so crews could safely remove trees and debris and restore power.
The government said up to 700 Canadian troops would be fanning out across the Maritimes to help restore electricity, clear roadways and evacuate residents in flooded areas
Nova Scotia Power chief executive Karen Hutt said over 400,000 Nova Scotia Power customers lost power at the peak of the storm and 50,000 had since been restored.
About 80% of Nova Scotia’s homes and businesses were blacked out, the highest in the company’s history.
Ms Hutt said some customers could remain without service for days.
On Prince Edward Island, about 75% of homes and businesses had no electricity by this afternoon, according to the province’s Public Safety Department.
Widespread blackouts affecting up to 80,000 NB Power customers were reported in southern New Brunswick.
By far the greatest devastation caused by the storm was in the Bahamas, where Dorian struck a week ago as a Category 5 hurricane with 185mph winds, and then hovered just offshore for more than a day and a half, obliterating thousands of homes.
Planes, cruise ships and yachts were evacuating people from the Abaco Islands and officials were trying to reach areas still isolated by flooding and debris.
The country’s National Emergency Management Agency said it was sending in extra staff because operations had been hampered by the storm’s impact on local workers.
The agency said it was setting up shelters or temporary housing for the newly homeless across the islands and appealed for Bahamians to take in storm victims.
Health Minister Duane Sands said today the death toll had risen by one to 44.
Dorian was blamed for five deaths in the US Southeast and one in Puerto Rico.
Meanwhile, floodwaters were receding from North Carolina’s Outer Banks, leaving behind a muddy trail of destruction.
The storm’s worst damage in the US appeared to be on Ocracoke Island, which even in good weather is accessible only by boat or air and is popular with tourists for its undeveloped beaches.
Residents who waited out the storm described strong winds followed by a wall of water that flooded the first floors of many homes and forced some to await rescue from their attics.
“We’re used to cleaning up dead limbs and trash that’s floating around,” said Ocracoke business owner Philip Howard said Saturday.
“But now it’s everything: picnic tables, doors, lumber that’s been floating around.”
Governor Roy Cooper said about 800 people had remained on the island to wait out Dorian, which made landfall on Friday morning over the Outer Banks as a far weaker storm than the monster that devastated the Bahamas.
The governor said officials were aware of no serious injuries on the Outer Banks from the storm. About 200 people were in shelters and 45,000 without power Saturday, according to the governor’s office. Emergency officials transported fuel trucks, generators, food and water to Okracoke.
Dorian also lashed the eastern tip of Maine with heavy rain, strong winds and high surf as the storm passed offshore.
Several hundred homes and businesses lost power.