Hurricane Irma becomes one of strongest storms ever recorded in Atlantic with winds reaching 185mph

Donald Trump declared a state of emergency on Tuesday as one of the strongest Atlantic storms on record barreled down on the southern United States.

The declarations authorise the Federal Emergency Management Agency to oversee disaster relief in Florida, Puerto Rico and the US Virgin Islands. Mr Trump acted after government meteorologists warned that Hurricane Irma could batter the country with “catastrophic” damage.

As the storm headed west toward Caribbean islands, putting it on a trajectory to slam into Florida, the National Hurricane Center recorded winds gusting at up to 185 miles an hour. That would make Irma one of the most powerful storms to emerge from the Atlantic.

Several islands in the storm’s path are on hurricane watch, the National Hurricane Center said said, warning in an advisory that “preparations to protect life and property should be rushed to completion.”

Four other storms have had winds that strong in the overall Atlantic Ocean 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 Key storm all had 185 mph winds.

Irma is so strong because of the unusually warm waters for that part of the Atlantic.

The Leeward Islands will be first to experience hurricane conditions, the NHC said, with Irma likely hitting there on Tuesday night before churning onward and bringing hurricane conditions to the Virgin Islands and Puerto Rico on Wednesday.

“Puerto Rico has not seen a hurricane of this magnitude in almost 100 years,” National Weather Service meteorologist Carlos Anselmi told The Associated Press.

Islands imperilled by the storm are likely to see a “life-threatening storm surge”, the hurricane center advisory warned, with the Virgin Islands potentially seeing “large and destructive waves” as waters rise by seven to 11 feet.

Those warnings have authorities bracing for the worst even as Houston still sifts through the wreckage of Hurricane Harvey.

The storm was moving west at 15 mph (24 kph), and the hurricane center said there was a growing possibility its effects could be felt in Florida later this week and over the weekend.

If it stays on the forecast track and reaches the Florida Straits, the water there is warm enough that the already “intense” storm could become much worse with wind speeds potentially reaching 225 mph, Kerry Emanuel, an MIT meteorology professor told the Associated Press.

“People who are living there (the Florida Keys) or have property there are very scared, and they should be,” Mr Emanuel said.