HURRICANE Milton headed into the Atlantic Ocean today after ploughing across Florida, pounding cities with ferocious winds and rain, whipping up a barrage of tornadoes. 

At least four deaths have been caused by the storm, which made landfall as a Category 3 storm Wednesday night in Siesta Key, about 70 miles south of Tampa. 

The St Petersburg area of Tampa recorded more than 16 inches of rain, prompting the National Weather Service to warn of flash flooding there as well as in other parts of western and central Florida.

The storm knocked out power across a large section of the US state, with more than 3.2 million homes and businesses losing electricity.

The fabric roof of Tropicana Field, home of the Tampa Bay Rays baseball team in St Petersburg, was ripped to shreds by the fierce winds. It was not immediately clear if there was damage inside. 

Before Milton even made landfall, heavy rain and tornadoes lashed parts of southern Florida on Wednesday morning, with conditions deteriorating throughout the day.

The Spanish Lakes Country Club near Fort Pierce, on Florida's Atlantic Coast, was hit particularly hard, with homes destroyed and some residents killed.

Four people were killed in tornadoes there, the St Lucie County Sheriff’s Office said.