Hurricane Ian left a path of destruction in south-west Florida, trapping people in flooded homes, damaging the roof of a hospital intensive care unit and knocking out power to two million people before aiming for the Atlantic Coast.

One of the strongest hurricanes to hit the United States barrelled across the Florida peninsula overnight on Wednesday, threatening catastrophic flooding inland, the National Hurricane Centre warned.

The centre’s 2am advisory said Ian was expected to emerge over Atlantic waters later on Thursday, with flooding rains continuing across central and northern Florida.

In Port Charlotte, along Florida’s Gulf Coast, the storm surge flooded a lower-level emergency department in a hospital even as fierce winds ripped away part of the roof from its intensive care unit (ITU), according to a doctor who works there.

Water gushed down on to the ICU, forcing staff to evacuate the hospital’s sickest patients – some of whom were on ventilators — to other floors, said Dr Birgit Bodine of the HCA Florida Fawcett Hospital.

Staff members used towels and plastic bins to try to mop up the sodden mess.

The medium-sized hospital spans four storeys but patients were forced into just two because of the damage.

Ms Bodine planned to spend the night there in case people injured from the storm arrive needing help.

“As long as our patients do OK and nobody ends up dying or having a bad outcome, that’s what matters,” she said.

Police in nearby Fort Myers received calls from people trapped in flooded homes or from worried relatives.

Pleas were also posted on social media sites, some with video showing debris-covered water sloshing toward homes’ eaves.

WORLD HurricaneIan
(PA Graphics)

Brittany Hailer, a journalist in Pittsburgh, contacted rescuers about her mother in North Fort Myers, whose home was swamped by five feet of water.

“We don’t know when the water’s going to go down. We don’t know how they’re going to leave, their cars are totalled,” Ms Hailer said.

“Her only way out is on a boat.”

Hurricane Ian turned streets into rivers and blew down trees as it slammed into south-west Florida on Wednesday with 150mph winds, pushing a wall of storm surge.

Ian’s strength at landfall was category four and tied it for the fifth-strongest hurricane, when measured by wind speed, to strike the US.

Ian dropped in strength by late Wednesday to category one, with 90mph winds as it moved overland.

Still, storm surges as high as six feet were expected on the opposite side of the state, in north-east Florida, on Thursday.

The storm was about 55 miles south west of Orlando with maximum sustained winds of 75mph at 2am on Thursday, the Miami-based hurricane centre said.

A man stands in the middle 7th Street in Ybor City on the rains soaked streets, a few hours before the high winds from Hurricane Ian hit Tampa
A man stands in the middle 7th Street in Ybor City a few hours before the high winds from Hurricane Ian hit Tampa (Willie J Allen Jr/Orlando Sentinel/AP)

A hurricane warning remained in effect north of Bonita Beach, about 31 miles south of Fort Myers, to Anclote River including Tampa Bay and from Sebastian Inlet to the Flagler/Volusia county line.

The centre discontinued a hurricane warning between Bonita Beach and Chokoloskee.

A tropical storm warning from Chokoloskee to Flamingo on the state’s south-west tip was also discontinued.

Hurricane-force winds were expected across central Florida until later on Thursday with widespread, catastrophic flooding likely, the hurricane centre said.

No deaths were reported in the United States from Ian by late Wednesday.

But a boat carrying Cuban migrants sank on Wednesday in stormy weather east of Key West.

Tropical Weather
Access roads to the Sunshine Skyway bridge are blocked off as the span is closed due to high winds from Hurricane Ian (Dirk Shadd/Tampa Bay Times via AP)

The US coastguard initiated a search-and-rescue mission for 23 people and managed to find three survivors about two miles south of the Florida Keys, officials said.

Four other Cubans swam to Stock Island, just east of Key West, the US Border Patrol said.

Air crews continued to search for possibly 20 remaining migrants.

The storm previously tore into Cuba, killing two people and bringing down the country’s electrical grid.

The hurricane’s eye made landfall near Cayo Costa, a barrier island just west of heavily populated Fort Myers.

As it approached, water drained from Tampa Bay.

More than two million Florida homes and businesses were left without electricity, according to the powerOutage.us site.

Nearly every home and business in three counties was without power.

Sheriff Bull Prummell of Charlotte County, just north of Fort Myers, announced a curfew between 9pm and 6am “for life-saving purposes”, saying violators may face second-degree misdemeanour charges.

“I am enacting this curfew as a means of protecting the people and property of Charlotte County,” Mr Prummell said.

The Weather Underground forecaster predicted the storm would pass near Daytona Beach and go into the Atlantic before veering back ashore in South Carolina on Friday.

The governors of South Carolina, North Carolina, Georgia and Virginia all preemptively declared states of emergency.

Forecasters predicted Ian will turn toward those states as a tropical storm, likely dumping more flooding rains into the weekend.