Ian has regained strength over the Atlantic Ocean and become a hurricane again, the National Hurricane Centre (NHC) said.
The storm had been downgraded to a tropical storm as it weakened over Florida. Hurricane Ian is now forecast to hit South Carolina on Friday as a Category 1 hurricane.
The storm is about 240 miles (390 kilometres) south of Charleston, South Carolina. A hurricane warning has been issued for the entire South Carolina and the southern end of the North Carolina coast.
A tropical storm warning is in effect for other parts of the North Carolina coast and the Georgia coast.
The hurricane had wind speeds up to 75 miles per hour (120 kilometres per hour) on Thursday afternoon. By Friday, winds are forecast to reach up to around 80 mph (129 kph).
Storm surge in parts of South Carolina could reach up to seven feet (2.1 metres) on Friday as some spots could see up to 12 inches (30 centimetres) of rain, NHC said.
“Considerable flash and urban flooding, and minor river flooding is possible across South Carolina,” the agency adds.
Residents in low-lying areas have been urged to prepare for the incoming storm, which wreaked havoc as it moved across Florida. On Thursday, the mayor of Charleston urged people to stay home and “take this storm seriously.”
The storm is forecast to continue inland toward Appalachian North Carolina and Virginia over the weekend.
Hurricane Ian hit southwestern Florida as a strong Category 4 storm on Wednesday, with winds quite nearly reaching Category 5 status. Officials are still assessing the damage, but the storm appears to have completely devastated the area around Fort Myers and Cape Coral, right near where the storm made landfall.
The storm quickly strengthened after moving over Cuba and turning toward Florida. This kind of “rapid intensification” is associated with the climate crisis, as warmer waters can quickly power up a storm, adding a lot more potential danger from wind and rain.
Hurricanes, on average, are forecast to get a lot stronger as the climate crisis grows over the next few decades.
As of Thursday, at least a dozen people had been confirmed dead, but damage assessments were still ongoing as the weather cleared and first responders worked on getting back into affected communities.
President Biden said that Hurricane could be the “deadliest” storm in Florida history on Thursday. The storm is one of the strongest on record to hit the state.