Hurricane Ian barreled north Friday, making a second landfall in South Carolina, two days after carving a path of destruction across central Florida.
Ian was upgraded to a Category 1 hurricane as it churned toward the Carolinas, with maximum sustained wind speeds of 85 miles per hour (140 kilometers per hour), the US National Hurricane Center (NHC) said.
After making landfall, the storm was downgraded from a hurricane to a post-tropical cyclone as it moved across South Carolina.
Hours before it made landfall on Friday afternoon, South Carolina's entire coastline was placed on alert, with authorities advising people to seek higher ground.
The warning stretched from the Savannah River to Cape Fear, with flooding rains likely across the Carolinas and southwestern Virginia, the NHC said.
Ian's trail of destruction
Ian was one of the most powerful storms to have struck the US in recent times, with President Joe Biden saying Thursday that it could be the deadliest hurricane in Florida's history.
At least 17 people have been killed by the hurricane so far, according to media reports.
Officials expect the death toll to rise as rescue teams reach affected areas, especially along Florida's Gulf Coast.
Kevin Guthrie, director of Florida's Division of Emergency Management, put the potential death toll at 21.
He said that some 10,000 people in Florida were unaccounted for, although many of them were likely in shelters or without power and unable to contact relatives.
Shortly before Ian made landfall in Florida on Wednesday, a boat carrying migrants sank, leaving 23 people missing and four survivors.
Florida Governor Ron DeSantis said Friday that rescue crews had gone door-to-door to over 3,000 homes in the hardest-hit areas.
"There's really been a Herculean effort,'' he said during a news conference in Tallahassee.
Earlier, he described how thousands of personnel were assigned to respond to the storm with 250 aircraft, 300 boats and 1,600 high-water vehicles.
Biden issued a federal disaster declaration, allowing federal aid to be provided to Florida.
Hurricane intensified after hitting Cuba
Ian had battered Cuba as a Category 3 storm just less than 24 hours before nearing Florida.
At least three people were killed on the island.
Scientists have long sounded the alarm over how climate change can increase the intensity of extreme weather events.