The most powerful Atlantic Ocean hurricane in recorded history made its first landfall in the islands of the northeast Caribbean early Wednesday.

The eye of Hurricane Irma passed over Barbuda around 1.47am, the National Weather Service said and could hit Puerto Rico, the Dominican Republic, Haiti and Cuba before possibly heading for Florida over the weekend.

Residents have already reported power lines coming down in the storm, while heavy rain and howling winds raked the neighboring island of Antigua, sending debris flying as people huddled in their homes or government shelters.

Officials warned people to seek protection from Irma’s “onslaught” in a statement that closed with: “May God protect us all.”

Camera Icon Wood panels are installed over a storefront window in preparation for Hurricane Irma in Carolina, Puerto Rico. Credit: AP

In Barbuda, the storm ripped off the roof of the island’s police station forcing officers to seek refuge in the nearby fire station and at the community centre that served as an official shelter.

The Category 5 storm also knocked out communication between islands. Midcie Francis of the National Office of Disaster Services confirmed there was damage to several homes, but said it was too early to do tally or assess the extent of the damage.

The storm had maximum sustained winds of 185m/h (295km/h), according to the U.S. National Hurricane Center. Its forecast early Wednesday was for the winds to fluctuate slightly but for the storm to remain at Category 4 or 5 strength for the next day or two.

The most dangerous winds, usually nearest to the eye, were forecast to pass near the northern Virgin Islands and near or just north of Puerto Rico through the day Wednesday.

“I hear it’s a Cat 5 now and I’m terrified,” Antigua resident Carol Joseph said. “I had to come back for more batteries because I don’t know how long the current will be off.”

Camera Icon Residents stock up in preparation for Hurricane Irma. Credit: Roberto Koltun/Miami Herald via AP

On the 108-square-mile island, people who live in low-lying areas were staying with friends and relatives on higher ground or sleeping in churches, schools and community facilities built to withstand hurricanes. None of the shelters have yet been tested by Category 5 winds, however.

Many homes in Antigua and Barbuda are not built on concrete foundations or have poorly constructed wooden roofs that are susceptible to wind damage. Other islands in the path of the storm included the Virgin Islands and Anguilla, a small, low-lying territory of about 15,000 people.

President Donald Trump declared emergencies in Florida, Puerto Rico and the U.S. Virgin Islands, and authorities in the Bahamas said they would evacuate six southern islands.

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 are usually home to warmer waters that fuel cyclones. 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.

The northern Leeward Islands were expected to see waves as high as 11 feet, while the Turks and Caicos Islands and southeastern Bahamas could see towering 20-foot waves later in the week, forecasters said.

“This is not an opportunity to go outside and try to have fun with a hurricane,“ U.S. Virgin Islands Gov. Kenneth Mapp warned. “It’s not time to get on a surfboard.”

Camera Icon In this GOES-East satellite image released by the National Oceanic and Atmospheric Administration, Hurricane Irma moves westward in the Atlantic Ocean toward the Leeward Islands. Credit: National Oceanic and Atmospheric Administration

Bahamas Prime Minister Hubert Minnis said his government was evacuating the six islands in the south 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 starting Wednesday in what he called the largest storm evacuation in the country’s history.

“The price you may pay for not evacuating is your life or serious physical harm,” Minnis said.

The 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.

“The dangerousness of this event is like nothing we’ve ever seen,” Puerto Rico Gov. Ricardo Rossello said. “A lot of infrastructure won’t be able to withstand this kind of force.”

The eye of the storm was expected to roar westward on a path taking it north of more heavily populated Puerto Rico, the Dominican Republic, Haiti and Cuba, but it could still cause life-threating storm surges, rains and mudslides.

Camera Icon Image released by the National Oceanic and Atmospheric Administrations shows the scale of Irma. Credit: NOAA

Florida Gov. Rick Scott activated 100 members of the Florida National Guard to be deployed across the state, and 7,000 National Guard members were to report for duty Friday when the storm could be approaching the area. On Monday, Scott declared a state of emergency in all of Florida’s 67 counties.

Officials in the Florida Keys geared up to get tourists and residents out of Irma’s path, and the mayor of Miami-Dade county said people should be prepared to evacuate Miami Beach and most of the county’s coastal areas.

Mayor Carlos Gimenez said the voluntary evacuations could begin as soon as Wednesday evening. He activated the emergency operation centre and urged residents to have three days’ worth of food and water.

The National Hurricane Center in Miami said hurricane-force winds extended 50 miles (85km) from Irma’s centre and tropical storm-force winds extended 175 miles (280km).

Also Wednesday morning, a new tropical storm formed in the Gulf of Mexico off Mexico’s coast. Tropical Storm Katia had maximum sustained winds of 40m/h (65km/h) with some strengthening forecast over the next two days. But the hurricane center said Katia was expected to stay offshore through Friday morning.