(Bloomberg) -- Ian, one of the most powerful storms in US history, carved a trail of ruin across southern Florida -- downing bridges, inundating roads and shattering homes -- and regained strength, threatening South Carolina with seven-foot (2 meter) waves.

The human toll remained unclear. President Joe Biden said at a Washington briefing Thursday that there were “early reports of what may be substantial loss of life.” CNN cited Florida officials with a death count of at least 15. An official from Volusia County, in the east-central part of Florida, said one man was confirmed dead.

Some 2.6 million homes and businesses were left without power while rivers overflowed and two bridges collapsed. Having hit the southwestern coast of Florida as a Category 4 hurricane at 150 miles (241 kilometers) per hour, Ian slowed inland to a tropical storm, dumping rain. After earlier being downgraded to a storm, it regained Category 1 hurricane strength and is expected to hit the Carolinas Friday, the National Hurricane Center said.

Florida Governor Ron DeSantis said that Chinook and Black Hawk helicopters had rescued people from flooded islands. He spoke with Biden, who approved a disaster declaration for the state.

“The impacts of this storm are historic,” DeSantis said. “We’ve never seen a flood event like this.”

Estimates of possible damage are in the tens of billions, with AccuWeather forecasting $100 billion. 

“This is the worst I’ve been through,” said Shanel Whitaker of Punta Gorda as she stood in line with about 50 others outside a Marathon filling station. The outlet had no electricity or gasoline.

Across Florida’s southwest, residents were trapped in their homes and a hospital roof was damaged, forcing patient evacuations to other floors. With limited electricity and cell phone coverage, some distress calls were going unanswered and the extent of the casualties was still being assessed. About 11% of the state’s cell phone networks were out of service.

A number of hospitals reported loss of water supply. A section of Sanibel Causeway was wiped out as was the Pine Island Bridge, which connects to the mainland. Both will require structural rebuilds, the governor said.

DeSantis said years of rebuilding were ahead from a storm that changed the very character of his state.

Governors in South Carolina, Georgia, North Carolina, and Virginia declared emergencies in advance of Ian’s arrival. 

By early Friday, winds were expected to rise in South Carolina and Georgia, the National Hurricane Center said. Heavy rains and flooding will continue across Florida. The warm waters of the Gulf Stream are adding to the storm’s strength.

Ian will likely hit just north of Charleston, South Carolina around noon Friday, driving a surge into the city of between 3 to 6 feet and dropping upwards to 8 inches of rain, said Mike Doll, a meteorologist at commercial-forecaster AccuWeather Inc. Power outages will reach far inland as Ian’s winds shake trees and power lines throughout the region.

The storm is likely to create an even higher flooding surge further up the coast, with as much as 10 feet of water being pushed on shore in places, he said.

“There is a danger of a life-threatening storm surge through Friday along the coasts of northeast Florida, Georgia, and South Carolina,” Eric Blake, a senior hurricane specialist at the center, wrote in a forecast.

Back in Florida, in Port Charlotte, a community of 54,000 at the confluence of where the Peace and Myakka rivers pour into the Gulf of Mexico, the roofs of submerged cars poked up above floodwaters blocking a road.

Fallen palms and power lines crisscrossed pavements and residential yards. In one driveway, a tree lay atop a smashed boat and automobile.

Most of the downed treetops were pointed west, toward the Gulf, a tell-tale sign that they fell when Ian’s counter-clockwise winds raged in from the east -- the same phenomenon that in some areas saw seawater pushed away from shore.

Filling stations were shut along Interstate 75 south of Tampa, leaving drivers on the main thoroughfare along Florida’s southwestern spine few options for obtaining gasoline or diesel.

Trucks hauling water-removal equipment and crews headed south on I-75 from Tampa toward the hardest-hit areas in places like Fort Myers, as did a flatbed stacked with portable toilets.

At least 19.3 inches (49 centimeters) of rain fell in North Point, Florida, near where the storm came ashore, according to the National Weather Service. Many measurement sites were knocked offline.

Rivers across central Florida set flooding records, according to the National Weather Service. Throughout the US Southeast, at least 31 river and tide gauges were recording flooding.

Ian came ashore Wednesday afternoon with winds of 150 miles (249 kilometers) per hour, tied for the fifth strongest hurricane to hit the mainland US, Jeff Masters and Bob Henson, meteorologists at Yale Climate Connections said. The monster storm pushed a 12-foot wall of water into Naples, Fort Myers and other cities, swamping cars, toppling buildings and knocking out power. 

The ninth storm of the 2022 Atlantic season, Ian could produce deluges as far as New Jersey. Flooding in Georgia could hurt cotton quality with many plants ready for harvest, said Don Keeney, a meteorologist at commercial forecaster Maxar.

Ian is also threatening to further upend Florida’s already unstable home-insurance market. The largest insurers reduced their presence in the state to dodge losses brought on by hurricanes, and smaller underwriters still active there have been forced to hike premiums and narrow coverage to keep pace with litigation and fraud.  

In addition, the state’s struggling citrus industry will also get an unwelcome test. Upwards of 90% of its groves, heavy with ripe fruit, were in the path of Ian’s winds. Florida, the US’s largest producer of orange juice, had been grappling with citrus greening that damages fruit and eventually kills trees. Futures prices were soaring before Ian.

After the then-record 2005 hurricane season, many citrus producers in Florida couldn’t fully restore operations, Rabobank analyst Andres Padilla said. “Intense damage to the crops could permanently remove some of the producers from the market,” he added.

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