Hurricane Irma: US-bound storm strengthens to Category 5, strongest possible on scale

US-bound Hurricane Irma has been upgraded to an "extremely dangerous" Category five storm, with winds reaching up tp 175 miles per hour, according to the National Weather Service.

The hurricane is moving west at around 14 mph, and is located around 270 miles east of Antigua, said the National Hurricane Center.

Florida, Puerto Rico and the US Virgin Islands have declared a state of emergency, and other states are bracing for the possible impact of extreme weather.

Florida Governor Rick Scott said: "Hurricane Irma is a major and life-threatening storm and Florida must be prepared." He said that the exact path of the storm was not known, but it could affect "millions of Floridians".

The Governor of the British Virgin Islands has urged those who could to evacuate the small island of Anegada before the storm hits.

Authorities anticipate Irma to cause flash floods by dumping up to 10 inches of rain, landslides and even produce waves of up to 23 feet.

The centre of the storm, which is the most powerful, is set to approach the northern Leeward Islands on Tuesday evening and early Wednesday morning, before hitting Puerto Rico by Thursday, possibly leaving residents without electricity for months due to a decade-long recession and crumbling infrastructure.

Irma formed in the far eastern Atlantic near the Cape Verde islands, and these storms frequently become the most intense, such as Hurricane Hugo, Floyd and Ivan.

Hurricane warnings have been issued to 12 Caribbean islands. By the time Irma reaches Puerto Rico, winds are expected to range between 40 and 50 mph, and between four and eight inches of rain.

Weather experts said the storm looks to be the strongest since Hurricane Felix in 2007, the most recent Category 5 hurricane to reach the US.

The National Hurricane Center said as of 8am ET Tuesday that it was too early to determine what direct impact Irma would have on the continental US, but it is expected to turn right and head north by the end of the week, along the eastern coast of the US. Local reports in Florida saw people spending Labor Day stocking up on goods to bunker down during Irma if needed, emptying shelves in supermarkets.

Poverty-struck islands like Haiti are still reeling from recent storms which caused humanitarian disasters.

Last year, Hurricane Matthew, another Category five, reached winds of 165 mph, causing great damage to the Caribbean Islands and more than 600 people died. In Haiti alone, more than 500 people died.

Hurricane Irma follows at least 63 deaths related to Hurricane Harvey, a Category three, which dumped as much as 1.3m rain in southeast Texas over a few days, as people were trapped in quickly rising floodwater. The storm caused billions in damage to reapri and many people are still out of their homes.

Texas Governor Greg Abbott suggested repair costs could total $180 billion. President Donald Trump requested a $7.9 billion downpayment from Congress towards Harvey relief efforts.