North Carolina and South Carolina were on alert Thursday as Ian made its way toward them after cutting a path of destruction through Florida and regaining strength over the Atlantic Ocean.

Downgraded to a tropical storm after striking Florida’s west coast as a major hurricane Wednesday, it strengthened again to a hurricane Thursday evening, the National Hurricane Center said.

A hurricane warning is in effect from the Savannah River in Georgia to Cape Fear in North Carolina, an area that includes the entire coast of South Carolina, where the storm is expected to make a direct hit. A tropical storm warning is in effect for parts of Florida, Georgia and North Carolina.

In anticipation of the storm, South Carolina Gov. Henry McMaster issued a state of emergency Wednesday. The governors of North Carolina and Georgia did the same.

“If you haven’t yet made plans for every contingency, this afternoon is the time to do so,” McMaster said Thursday. “We can expect to experience a lot of rain throughout the state along with dangerous storm surge in low-lying coastal areas. With the potential for hurricane force winds along our coast, it’s important for South Carolinians to plan now.”

South Carolina officials said this could be the first hurricane to make direct landfall there since Hurricane Matthew in 2016, which brought a large amount of flooding to the state. According to forecasts, Ian could bring storm surges as high as 4 to 7 feet to South Carolina’s coast.

The city of Charleston, South Carolina, which routinely floods and faces a possible direct hit from the storm, opened sites for residents to pick up sandbags to protect their homes. City leaders were working with state and county officials to coordinate a response and specifically warned those in low-lying areas to make extra preparations.

“The big thing is we want everybody to be cautious, don’t panic, be prepared and have a plan of how you’re going to take care of yourself and your loved ones,” Ben Almquist, the emergency management director for the City of Charleston, said, according to local NBC News-affiliate WCBD.

The hurricane, which was about 240 miles south of Charleston, had maximum sustained winds of 75 mph and was moving north-northeast at 10 mph, according to the National Hurricane Center’s 5 p.m. update. The storm “could slightly strengthen” before it reaches land, the hurricane center said.

Ian is expected to approach the coast of South Carolina on Friday and move inland across the Carolinas on Friday night and Saturday, rapidly weakening as it moves across land, according to the hurricane center.

While South Carolina faces the largest threat from the storm, North Carolina and Georgia also could see significant flood events because of the downpours and storm surges created by Ian.

“This storm can still be dangerous and even deadly,” North Carolina Gov. Roy Cooper said at a press briefing Thursday. “Heavy rains, up to 7 inches in some areas, are likely to bring flooding, landslides threaten our mountains and there’s a chance of tornadoes and statewide coastal flooding.”

William Ray, director of the North Carolina Department of Emergency Management, said at the same briefing that the department had positioned 350 personnel at the state’s operations center and three other regional centers to support any necessary response. He said the department did not yet, for the most part, recommend evacuations, but he said residents should remain vigilant.

That was a common refrain from officials in all three states, as they urged residents to stay on alert even though the storm has been downgraded after its catastrophic arrival in Florida.

“Just because it’s no longer hurricane doesn’t mean storms can’t be deadly,” said Daniel Kaniewski, who served as a deputy administrator at the Federal Emergency Management Agency during the Trump administration. “As we saw with Hurricane Ida, there were more fatalities from that storm in New York, New Jersey than there were in Louisiana.”

Ida, which initially hit Louisiana last year before making its way to the northeast, came as a surprise to many in New York and New Jersey. The flooding caught officials and residents there flat-footed.

Kaniewski, who is now the managing director of the risk management and strategy firm Marsh McLennan, said the flooding risks after a hurricane strikes can be significant — even as it weakens.

Though Ian is now a tropical storm, it still has the strength to dump a huge amount of rain on the Carolinas and Georgia. It can also draw significant amounts of water up rivers and streams, creating immense flood risks.

Kaniewski said it could prove to be “absolutely catastrophic depending on the environment and where that water ends up.”

“The key point, just as it was the key point before it made landfall in Florida, is that citizens should heed the advice of local officials because these impacts can be highly localized and the local officials will know based on the modeling what the impacts are likely to be,” he said.