The hurricane had winds up to 150 mph (240 kph), just shy of a Category 5 storm, as it blew off roofs, uprooted trees and caused other damage on Carriacou, one of the islands of Grenada, and elsewhere in the southeast Caribbean.

"This is an extremely dangerous and life-threatening situation,” the National Hurricane Centre said.

Hurricane warnings were in effect for Barbados, Grenada, Tobago and St. Vincent and the Grenadines as thousands of people hunkered down in homes and shelters. The last strong hurricane to hit the southeast Caribbean was Hurricane Ivan 20 years ago, which killed dozens of people in Grenada.

NBC Radio in St. Vincent and the Grenadines said it received reports of roofs being torn off churches and schools as communications began collapsing across the southeast Caribbean.

“Jesus Christ!” one woman could be heard yelling in a video that shows tin roofs flying through the air.

Late Monday morning, Beryl was located about 30 miles (50 kilometers) northeast of the island of Grenada, with maximum sustained winds of 150 miles (240 kilometers) per hour, and was moving west-northwest at 20 mph (31 kph).

Officials in Barbados received more than a dozen reports of roof damage, fallen trees and downed electric posts across the island, said Kerry Hinds, emergency management director.

Once Beryl passes, drones will assess damage and speed up response, said Wilfred Abrahams, minister of home affairs and information. Before, it used to take two hours to receive information as crews fanned out across the island, versus seven minutes with drones, he noted.

A tropical storm warning was in effect for St. Lucia, Martinique and Trinidad. A tropical storm watch was issued for Haiti's entire southern coast, and from Punta Palenque in the Dominican Republic west to the border with Haiti. A hurricane watch was issued for Jamaica.

Forecasters warned of a life-threatening storm surge of up to 9 feet (3 metres) in areas where Beryl made landfall, with 3 to 6 inches (7.6 to 15 centimeters) of rain for Barbados and nearby islands and possibly 10 inches in some areas (25 centimeters), especially in Grenada and the Grenadines.

The storm was expected to weaken slightly over the Caribbean Sea on a path that would take it just south of Jamaica and later toward Mexico's Yucatan Peninsula as a Category 1.

“It should be emphasised that Beryl is forecast to remain a significant hurricane during its entire trek across the Caribbean region,” the National Hurricane Centre said.

Officials in some southeast Caribbean islands announced controlled shutdowns of electricity and warned of water outages ahead of the storm, urging people to seek shelter. They warned of landslides and flash flooding as they shuttered schools, airports and government offices.

Hours before the storm, Barbadian Michael Beckles said he feared the worst for his island despite witnessing how people were taking it seriously.

“As prepared as we can try to be, there are a lot of things that we can't control,” he said. “Electricity probably will go. We'll have issues with water. There are a lot of houses that are not ready for a storm like this.”

Historic hurricane

Beryl strengthened from a tropical depression to a major hurricane in just 42 hours — a feat accomplished only six other times in Atlantic hurricane history, and with September 1 as the earliest date, according to hurricane expert Sam Lillo.

It also was the earliest Category 4 Atlantic hurricane on record, besting Hurricane Dennis, which became a Category 4 storm on July 8, 2005.

“This is a dangerous hurricane for the Windward Islands," said hurricane specialist and storm surge expert Michael Lowry, who warned that when Beryl comes ashore, “it's going to be a very serious situation.”

Beryl amassed its strength from record warm waters that are hotter now than they would be at the peak of hurricane season in September, he said.

Beryl also marked the farthest east that a hurricane has formed in the tropical Atlantic in June, breaking a record set in 1933, according to Philip Klotzbach, Colorado State University hurricane researcher.

Among those weathering the storm was Jaswinderpal Parmar of Fresno, California, who had travelled to Barbados for Saturday's Twenty20 World Cup final, cricket's biggest event. He and his family were now stuck there with scores of other fans, their flights cancelled on Sunday.

He said by phone that it's the first time he has experienced a hurricane, with heavy rain starting at midnight. He and his family have been praying, as well as taking calls from concerned friends and family as far away as India.

“We couldn't sleep last night,” Parmar, 47, said. “We were keeping an eye on it."

Looking ahead

Even as Beryl bore down on the southeast Caribbean, government officials warned about a cluster of thunderstorms mimicking the hurricane's path that have a 70 per cent chance of becoming a tropical depression.

“There's always a concern when you have back-to-back storms,” Lowry said. “If two storms move over the same area or nearby, the first storm weakens the infrastructure, so the secondary system doesn't need to be as strong to have serious impacts.”

Beryl is the second named storm in the Atlantic hurricane season, which runs from June 1 to November 30. Earlier this month, Tropical Storm Alberto made landfall in northeast Mexico and killed four people.

On Sunday night, a tropical depression near the eastern Mexico coastal city of Veracruz briefly strengthened into Tropical Storm Chris, the third named storm of the season. It weakened on Monday and was downgraded back to a tropical depression forecast to move inland. The National Hurricane Centre early Monday reported heavy rainfall and flooding, with the possibility of mudslides, before the storm dissipates.

The National Oceanic and Atmospheric Administration predicts the 2024 hurricane season is likely to be well above average, with between 17 and 25 named storms. The forecast calls for as many as 13 hurricanes and four major hurricanes.

An average Atlantic hurricane season produces 14 named storms, seven of them hurricanes and three major hurricanes.