Hurricane Melissa death toll nears 50 as storm heads for Bermuda

The death toll from Hurricane Melissa has risen to nearly 50 after the ferocious storm devastated Caribbean islands and was bearing down on Bermuda.

Flooding was expected to subside in the Bahamas, although high water levels could persist in Cuba, Jamaica, Haiti and the Dominican Republic, the US National Hurricane Centre (NHC) said.

The storm, one of the most powerful recorded, was made four times more likely because of human-caused climate change, a study by Imperial College London found.

Tropical storm conditions were observed in Bermuda late on Thursday and a hurricane warning was issued for the island, with maximum sustained winds of 160 kilometres per hour, the NHC said.

The government urged residents to take precautionary measures against the still-powerful storm.

Residents remained calm as Melissa was expected to give the island a relatively wide berth. Authorities said they would close its causeway on Thursday night and shut schools and ferries on Friday "out of an abundance of caution".

In the Bahamas, which Melissa cut through overnight, authorities lifted storm warnings but did not give the all-clear. An official said authorities expected to decide by Saturday whether it was safe for the hundreds of people who evacuated from affected islands to return to their homes.

Melissa did not directly hit Haiti, but caused at least 25 deaths there, authorities said, mostly in the southern town of Petit Goave when a river burst its banks after days of torrential rain.

A river also caved in and carried off part of a national motorway, local newspaper Le Nouvelliste reported. The road, which had been weakened by last year's Hurricane Beryl, connected to the nearby city of Jacmel.

Melissa was the first major hurricane since 1988 to directly hit Jamaica, where authorities reported at least four deaths in the south-western region site of the hurricane's landfall as a powerful Category 5 storm. Wind speeds were well above the minimum level for the strongest hurricane classification.

US forecaster AccuWeather said Melissa was the third most intense hurricane observed in the Caribbean, as well as its slowest moving, compounding damages for affected areas.

Satellite imagery showed trees and homes devastated in the hardest-hit areas of Jamaica, sparse remaining greenery defoliated and most structures destroyed.

"I know many Jamaicans are concerned about their loved ones," Prime Minister Andrew Holness said in a video message from a helicopter as he headed to hard-hit Westmoreland parish.

Jamaica's military called on reserve personnel to report for duty in relief and rescue operations. More than 70 per cent of electrical customers in Jamaica remained without power as of Thursday morning, said Energy Minister Daryl Vaz, with power lines felled across the island's roads.

Many schools remained without power or water, officials in the capital Kingston said.

More than 130 roads remained blocked by trees, debris and electric lines, authorities said, forcing the military to clear roads on foot into isolated areas, with ambulances following close behind.

One road in the hard-hit coastal town of Black River was swamped with more than 1.2 metres of sand stretching over 1.5km, officials said.

In western parts of the island, people crowded by supermarkets and petrol stations to fill up on supplies.

US search and rescue teams were headed for Jamaica on Thursday to assist in recovery efforts, Jamaican authorities said. Secretary of State Marco Rubio said the US was prepared to offer "immediate humanitarian aid" to the people of Cuba, a long-time US foe.

Authorities in Cuba, which Melissa struck as a Category 3 storm, said they were "awaiting clarification on how and in what way they are willing to assist".

At least 241 Cuban communities remained isolated and without communications on Wednesday after the storm's passage across Santiago province, affecting up to 140,000 residents, according to preliminary media reports.

Residents of Santiago, Cuba's second-largest city, began returning to repair their homes. Authorities had evacuated 735,000 people to shelters outside the hurricane's cone and relocated tourists in small northern islands to inland hotels. Cuba reported substantial infrastructure and crop damage but no loss of life as of midday on Thursday.