Hurricane Fiona pummelled Bermuda with heavy rains and winds early on Friday, on its way up to Canada’s Atlantic coast.
Officials in Canada have urged residents in the country’s eastern provinces to prepare for coastal flooding and power outages.
Fiona is expected to hit Canada’s shores by Saturday morning.
Florida also faces a hurricane threat after a separate tropical cyclone formed in the Caribbean Sea.
Tropical Depression Nine is in its early stages and is moving on a path that could bring it to Florida next week as Hurricane Hermine, according to the National Hurricane Center.
Hurricane Fiona, now a Category 3 storm, had already wreaked havoc on Puerto Rico and the Dominican Republic earlier this week, and many are still left with no power or running water.
Five people have died across the Caribbean: one in Guadeloupe, two in Puerto Rico and two in the Dominican Republic.
In Bermuda, Hurricane Fiona forced schools and offices to close.
The National Hurricane Center has said Fiona’s maximum sustained winds could hit 130 mph (215 kph).
Canadian officials and meteorologists are urging residents to brace themselves for the storm’s impact as it reaches the Atlantic provinces of Nova Scotia, Prince Edward Island and Newfoundland.
The region could receive up to six to 10 inches of rain, increasing the risk of flash flooding.
Shelters have been prepared in Halifax and Cape Breton in Nova Scotia for people to take cover ahead of the storm.
“Every Nova Scotian should be preparing,” said John Lohr, the minister responsible for emergency preparedness in the province, in a Thursday press conference.
Mr Lohr added the storm may be “very dangerous”.
“The storm is expected to bring severe and damaging wind gusts, very high waves, and coastal storm surges, intense and dangerous rainfall rates and prolonged power outages,” Mr Lohr said.
Severe hurricanes in Canada are rare, as storms lose their energy once they hit colder waters in the north and become post-tropical instead. But pressure in the region is predicted to be historically low as Hurricane Fiona hits, making way for a heavier storm.
Nova Scotia was last battered by a tropical cyclone in 2003 with Hurricane Juan, a Category 2 storm that killed two people and heavily damaged structures and vegetation.