Australia Weather News

People in Florida and the Bahamas have looked on in disbelief as the force of Hurricane Irma appeared to suck shorelines bare and expose sea beds.

The hurricane, since downgraded to category one, submerged streets and knocked out power to millions in Miami, and threatened the highly populated Tampa Bay area with dangerous storm surges as it moved north.

Irma's powerful winds pulled water away from parts of the coast to feed the storm surges.

Those areas experienced a "bulge" of ocean water — the low pressure and strong winds at the centre of the storm suck the air and water inwards, creating a massive build-up of water.

Extraordinary images showed shorelines completely sucked dry in the Bahamas, which had avoided Irma's wrath.

"I am in disbelief right now. This is Long Island, Bahamas and the ocean water is missing," a Twitter user posted alongside vision.

Ocean waters also receded in Tampa, as the area on Florida's west coast waited for the worst of the storm to arrive.

Barrie Drewitt-Barlow, who is in Tampa, told ABC News:

"At the moment, the water on the bay has completely left, so it just looks like a mud pile just everywhere all over."

"What they're all saying is that's all going to flood Miami, but then it's going to surge back, and it's going to come to about 15 to 25 foot."

Two manatees became stranded after water receded out of Sarasota Bay in Manatee County.

Marcelo Clavijo, who uploaded vision of the manatees to Facebook, said a handful of locals helped move the mammals about 90 metres towards the water using plastic sheets.

The Florida Fish and Wildlife Conservation Commission said they were not intervening because manatees were used to being stranded at low tide, according to local newspaper Bradenton Herald.

Authorities warned the water would "rapidly surge back" into shorelines once winds change direction.