Hurricane Dorian has marched from the USA to Canada, knocking out power to hundreds of thousands of people, ripping roofs off apartment buildings, toppling a huge construction crane and uprooting trees.

There were no reported deaths as Dorian hit near the city of Halifax on Saturday afternoon, however the storm was blamed for at least 49 elsewhere along its path.

An estimated 70,000 people in the Bahamas have been left homeless after the devastating category four hurricane caused unprecedented damage to the archipelago before weakening as it moved towards America and Canada.

The US National Hurricane Center said the post-tropical cyclone was centred about 65km east of Chevery, Quebec, early on Sunday afternoon.

Top sustained winds had slipped to 120km/h, just above the threshold of hurricane force.

It was heading to the northeast, roughly up the St Lawrence River, at 41km/h.

The track would bring the storm near or over northwest Newfoundland or east Labrador during the afternoon and over the North Atlantic in the evening.

The government said that up to 700 Canadian military personnel will 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 there were more than 400,000 Nova Scotia Power customers without power at the peak of the storm and 50,000 have since had power restored.

But she said some could remain without service for days.

From Fox News – Dorian topples crane in Canada, causes widespread blackouts as storm marches north.https://t.co/gVu5w5a70E

— Kathleen Hunter (@KateHun49524279) September 8, 2019

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 295km/h 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.

The government said at least 43 people died due to the storm. 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.

-AAP