Hurricane Beryl has barrelled toward Jamaica as a powerful category four storm after battering smaller islands in the eastern Caribbean.

Scientists have cited human-caused climate change as the likely culprit for the storm’s rapid strengthening.

The unusually early hurricane downed power lines and unleashed flash floods. It has so far claimed at least three lives.

Beryl, the 2024 Atlantic season’s first hurricane and the earliest storm on record to reach the highest category on the Saffir-Simpson Scale, hit St Vincent and the Grenadines especially hard, according to Prime Minister Ralph Gonsalves.

Late on Monday, Beryl was at category five strength, but weakened slightly on Tuesday (local time).

“The hurricane has come and gone, and it has left in its wake immense destruction,” Gonsalves said.

On one island in the Grenadines archipelago, Union Island, 90 per cent of homes had been “severely damaged or destroyed”, he said.

Gonsalves confirmed one death, and said more fatalities could be confirmed in the coming days.

In a video briefing on Tuesday, Grenada’s prime minister, Dickon Mitchell, stressed that Carriacou and Petite Martinique, two of the three islands that make up the country, bore the brunt of the natural disaster.

“The situation is grim. There is no power. There is almost complete destruction of homes and buildings,” he said, citing impassable roads due to downed power lines and destroyed fuel stations crimping supplies.

Mitchell said at least two deaths were attributed to the impact of Beryl so far.

The hurricane, packing maximum sustained winds of 249km/h, was about 781 kilometres east-south-east of the Jamaican capital of Kingston, according to an advisory from the US National Hurricane Centre on Tuesday.

The NHC estimated that the massive weather system was moving west-north-west at a speed of 35km/h.

“Beryl is forecast to remain a powerful hurricane as it moves across the Caribbean Sea later this week”, an NHC post said. It said hurricane warnings were in effect for Jamaica and the Cayman Islands.

In Jamaica, men hauled fishing boats out of the water and tied them down in preparation for the hurricane’s arrival, while others noted there was still time to prepare on Tuesday.

“We Jamaicans don’t take things serious,” said Standford Pusey, as he showed off items secured with plastic tarps.

In Fort-de-France on the French Caribbean island of Martinique, north of St Vincent, video shared on social media showed heavy flooding in the streets as locals attempted to clear away debris.

NHC also issued a hurricane watch for the southern coast of Haiti.

Some weakening was expected, but Beryl will likely remain at major hurricane strength and is expected to bring 10-30 centimetres of rain to Jamaica and south-western Haiti by late Wednesday, according to the NHC forecast.

Dozens of shipping vessels in the storm’s path risk being affected, with diversions in the Caribbean, according to Vortexa, which provides energy-cargo tracking data.

The unusually early timing and rapid intensification of the storm was partly due to warmer ocean temperatures, scientists said.

Climate change likely contributed to Beryl’s early formation, while also driving how quickly it intensified, according to scientists surveyed by Reuters, which could provide an unsettling preview of future storms.

Global warming had helped push temperatures in the North Atlantic to record highs, said Christopher Rozoff, an atmospheric scientist at the US National Centre for Atmospheric Research. The warmer waters led to more evaporation, which fuelled more intense hurricanes featuring higher wind speeds, he said.

Beryl jumped from a category one to a category four storm in under 10 hours, according to Andra Garner, a Rowan University meteorologist. It was the fastest intensification recorded before September, the peak of the Atlantic hurricane season, she said.

Video from Barbados showed waves pounding the shore of the island, breaching walkways, felling palm trees and flooding roads in Bridgetown, the capital.

Beryl is also expected to approach Mexico’s Yucatan Peninsula, dotted with beach resorts popular with tourists, on Thursday.