SAN JUAN, Puerto Rico (AP) — Heavy rain and historic, 185-mph winds lashed the Virgin Islands and Puerto Rico’s northeast coast Wednesday as Hurricane Irma roared through Caribbean islands on its way to a possible hit on Florida.

The strongest Atlantic Ocean hurricane ever measured destroyed homes and flooded streets across a chain of small islands in the northern Caribbean, passing directly over Barbuda and leaving the island of some 1,700 people unable to communicate with the outside world.

Midcie Francis, spokesperson for the National Office of Disaster Services for Antigua and Barbuda, said the government had so far confirmed one death on Barbuda and heavy destruction on the island.

“A significant number of the houses have been totally destroyed,” said Lionel Hurst, the prime minister’s chief of staff.

France sent emergency food and water rations to the French islands of Saint Martin and Saint Barthelemy, where Irma ripped off roofs and knocked out all electricity.

The Agence France-Presse (AFP) reported that France said two people had been killed on St Barts and St Martin after the two eastern Caribbean islands were hit by Hurricane Irma, and announced it would set up an emergency fund to help them rebuild.

“At the present moment, there are reports of two dead and two seriously injured,” the French minister for overseas affairs, Annick Girardin, told the news channel BFMTV. “But obviously, the situation can change very, very quickly.”

By Wednesday evening the centre of the storm was 40 miles northwest of St Thomas in the US Virgin Islands and 55 miles northeast of San Juan, Puerto Rico, and heading west-northwest at 16 mph (26 kph).

The US National Weather Service said Puerto Rico had not seen a hurricane of Irma’s magnitude since Hurricane San Felipe in 1928, which killed a total of 2,748 people in Guadeloupe, Puerto Rico and Florida.

“We have to prepare for the worst,” Puerto Rico Governor Ricardo Rossello said. “If we don’t, it could be devastating.”

Puerto Rico’s public power company has cut back on staff and maintenance amid a decade-long economic crisis and the agency’s director warned that some areas could be without power from four to six months because the infrastructure has already deteriorated so badly.

Outages were reported in some neighbourhoods well ahead of the storm, with more than a half million people without power and more than 4,500 without water by Wednesday evening.

The federal government stepped in, with President Donald Trump this week approving an emergency declaration for the US Virgin Islands and Puerto Rico.

That means the Federal Emergency Management Agency and other agencies can remove debris and give other services that will largely be paid for by the US government.

EPA officials said their biggest concerns were oil spills and power disruptions to water supply systems.

“No matter what precautions we take, the coastal flooding will impact oil tanks,” said Catherine McCabe, a regional administrator.

Another concern was the 20 Superfund sites in Puerto Rico and the three in the US Virgin islands, given that most were near the coast, she said. She said EPA officials in New Jersey were on standby to fly down after the hurricane passed through.

State maintenance worker Juan Tosado said he was without power for three months after Hurricane Hugo killed dozens of people in Puerto Rico in 1989.

“I expect the same from this storm,” he said. “It’s going to be bad.”

Tourist Pauline Jackson, a 59-year-old registered nurse from Tampa, Florida, puffed on her last cigarette as a San Juan hotel prepared to shutter its doors ahead of the storm.

“I’m in a hurricane here, and when I get home, I’ll be in the same hurricane. It’s crazy,” she said.

She tried to leave ahead of the storm but all flights were sold out, and she worried about her home in Tampa.

“When you’re from Florida, you understand a Category 5 hurricane,” said Jackson, who was scheduled to fly out Friday.

The US National Hurricane Center said Irma’s winds would fluctuate, but the storm would likely remain at Category 4 or 5 for the next day or two as it roared past Puerto Rico, the Dominican Republic, Haiti, Cuba, the Turks & Caicos and parts of the Bahamas.

By early Sunday, Irma is expected to hit Florida, where Gov. Rick Scott said he planned to activate 7,000 National Guard soldiers by Friday and warned that Irma is “bigger, faster and stronger” than Hurricane Andrew. Andrew pummelled south Florida 25 years ago and wiped out entire neighbourhoods with ferocious winds.

Trump also declared an emergency in Florida, and authorities in the Bahamas said they were evacuating six southern islands.

Experts worried that Irma could rake the entire Florida east coast from Miami to Jacksonville and then head into Savannah, Georgia, and the Carolinas, striking highly populated and developed areas.

“This could easily be the most costly storm in US history, which is saying a lot considering what just happened two weeks ago,” said Brian McNoldy, a hurricane researcher at the University of Miami.

The mayor of Miami-Dade County said people should be prepared to evacuate Miami Beach and most coastal areas as soon as Wednesday evening. He activated the emergency operation centre and urged residents to have three days’ worth of food and water.

The State Department authorised voluntary evacuation of US diplomats and their families from the Dominican Republic, Haiti and Cuba, where the storm was expected to arrive by Friday.

Warm water is fuel for hurricanes and Irma was moving over water that was 1.8 degrees (1 degree Celsius) warmer than normal. Four other storms have had winds as strong in the overall Atlantic region, but they were in the Caribbean Sea or the Gulf of Mexico, which usually have warmer waters. Hurricane Allen hit 190 mph in 1980, while 2005’s Wilma, 1988’s Gilbert and a 1935 great Florida Keys storm all had 185 mph winds.

Bahamas Prime Minister Hubert Minnis said his government was evacuating six islands because authorities would not be able to help anyone caught in the “potentially catastrophic” wind, flooding and storm surge. People there would be flown to Nassau in what he called the largest storm evacuation in the country’s history.

The northern parts of the Dominican Republic and Haiti could see 10 inches (25 centimetres) of rain, with as much as 20 inches (50 centimetres) in the southeast Bahamas and Turks and Caicos. The website cruisecritic.com said 28 cruises had been cancelled, shortened or had their itineraries changed as a result of the hurricane.

Also Wednesday, Tropical Storm Katia formed in the Gulf of Mexico off Mexico’s coast and rapidly became a hurricane. It had sustained winds of 75 mph (120 kph) by the afternoon and the government of Mexico issued a hurricane watch for the coast of Veracruz state from Tuxpan to Laguna Verde.

Katia was about 185 miles (300 kilometres) north-northeast of the city of Veracruz and was expected to drift toward the coast on Thursday, the hurricane centre said.

Another tropical storm farther east in the Atlantic became a hurricane Wednesday evening. Hurricane Jose posed no immediate threat to land but meteorologists warned the storm’s path could change. Jose had winds of 75 mph (120 kph) and was quickly strengthening.