Hurricane Beryl -- the earliest-ever Category 4 storm in the Atlantic -- swept quickly across several islands in the southeastern Caribbean on Monday, dumping heavy rain and unleashing devastating winds as it churned towards Jamaica.

Carriacou Island, which is part of Grenada, took a direct hit early in the day from the storm's "extremely dangerous eyewall," with sustained winds at upwards of 150 miles (240 kilometers) per hour, the US National Hurricane Center (NHC) said.

Nearby islands, including Grenada and St. Vincent and the Grenadines, also experienced "catastrophic winds and life-threatening storm surge" according to the NHC.

Video obtained by AFP from St. George's in Grenada showed heavy downpours with trees buffeted by gusts.

"In half an hour, Carriacou was flattened," Grenada's Prime Minister Dickon Mitchell told a press conference.

"We are not yet out of the woods," Mitchell added, noting that while there were no deaths reported so far, he could not say for sure that none had occurred.

Later on social media, Mitchell said the government was working to get relief supplies to both Carriacou and the island of Petite Martinique on Tuesday.

"The state of emergency is still in effect. Remain indoors," he wrote on Facebook.

- Rare early strong storm -

Beryl became the first hurricane of the 2024 Atlantic season on Saturday and quickly strengthened to Category 4.

Experts say that such a powerful storm forming this early in the Atlantic hurricane season -- which runs from early June to late November -- is extremely rare.

It is the first hurricane since NHC records began to reach the Category 4 level in June.

"Only five major (Category 3+) hurricanes have been recorded in the Atlantic before the first week of July," hurricane expert Michael Lowry posted on social media platform X.

Barbados appeared to be spared from the worst of the storm but was still hit with high winds and pelting rain, though officials reported no injuries so far.

Barbados seems to have "dodged a bullet," Minister of Home Affairs and Information Wilfred Abrahams said in an online video, but nonetheless "gusts are still coming, the storm-force winds are still coming" he said.

Homes and businesses were flooded in some areas, and fishing boats were damaged in Bridgetown.

The storm prompted the cancellation of classes on Monday in several of the islands, while a meeting this week in Grenada of the Caribbean regional bloc CARICOM was postponed.

At 0000 GMT Tuesday, the storm was moving away from the Windward Islands and into the Caribbean Sea.

"Beryl is expected to remain an extremely dangerous major hurricane as it moves over the eastern Caribbean" Tuesday, the NHC said, adding that Jamaica had issued a hurricane warning, ahead of the storm's expected arrival on Wednesday.

The NHC also warned the Cayman Islands and areas on the Yucatan Peninsula to monitor the storm's progress.

- Extreme weather -

A Category 3 or higher on the Saffir-Simpson scale is considered a major hurricane, and a Category 4 storm packs sustained winds of at least 130 miles per hour.

The US National Oceanic and Atmospheric Administration said in late May that it expects this year to be an "extraordinary" hurricane season, with up to seven storms of Category 3 or higher.

The agency cited warm Atlantic Ocean temperatures and conditions related to the weather phenomenon La Nina in the Pacific for the expected increase in storms.

Extreme weather events including hurricanes have become more frequent and more devastating in recent years as a result of climate change.

© Agence France-Presse