BRIDGETOWN, Barbados (AFP) — Beryl, the first hurricane of the 2024 Atlantic season, strengthened into a “very dangerous” Category 3 storm Sunday morning as it threatened the southeast Caribbean with potential life-threatening winds and storm surge, US forecasters said.

The US National Hurricane Center (NHC) said Beryl — currently churning in the Atlantic Ocean about 420 miles (675 kilometres) east of Barbados — “continues to quickly strengthen this Sunday morning”.

“The storm is now a very dangerous Category 3 hurricane,” it said, warning that the storm’s eye is expected to move early on Monday across the Windward Islands, a cluster of islands including Martinique, Saint Lucia and Grenada.

Beryl is “continuing to rapidly intensify,” the NHC forecast said, indicating the storm would strengthen even further to an “extremely dangerous Category 4 hurricane” by the time it hit those Caribbean communities.

Meanwhile in the Barbadian capital of Bridgetown, cars were seen lined up at gas stations, while supermarkets and grocery stores were crowded with shoppers buying food, water and other supplies. Some households were already boarding up their properties.

Barbados, Saint Lucia, Saint Vincent and the Grenadines, Grenada and Tobago were all under hurricane warnings, while tropical storm warnings or watches were in effect for Martinique and Dominica, the NHC said in its latest advisory.

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 (209 kilometres per hour).

Beryl was packing maximum sustained winds that had increased to near 115 mph, the NHC said around 8:00 am (1200 GMT) Sunday, as it warned of “life-threatening winds and storm surge” in the Windward Islands.

“Devastating wind damage is expected where the eyewall of Beryl moves through portions” of the islands, the NHC said, indicating wind speeds in some locations could be 30 per cent stronger than those listed in their advisory.

Such a powerful storm forming this early in the Atlantic hurricane season — which runs from early June to late November — is extremely rare, experts said.

“Only five major (Category 3+) hurricanes have been recorded in the Atlantic before the first week of July. Beryl would be the sixth and earliest this far east in the tropical Atlantic,” hurricane expert Michael Lowry posted on social media platform X.

“Hurricane conditions are expected in the hurricane warning area beginning early on Monday,” the NHC said, warning of heavy rain, flooding and storm surge that could raise water levels as much as nine feet (2.7 metres) above normal.

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.