Up to 1.5 million Americans were fleeing as Hurricane Matthew — which has already killed more than 100 across the Caribbean — eyed the south Atlantic coastal U.S. as a Category 4 storm.
The hurricane, which had dipped to a Category 3, regained strength late Thursday morning, with maximum sustained winds at 140 mph, the National Hurricane Center said.
"Extremely dangerous Hurricane Matthew heading for Florida," the Hurricane Center warned.
Evacuations were under way in Florida, Georgia and South Carolina after Matthew, which hammered Haiti and strafed Cuba, began battering the Bahamas. The storm killed at least 114 across the Caribbean, including a staggering , and forecasters warned of "life-threatening" devastation as it crossed the Bahamas.
Florida in particular looked set to get walloped. President Obama signed an emergency declaration for the state, and Gov. Rick Scott activated 3,500 members of the National Guard.
Tropical storm conditions were expected in Florida Thursday before Matthew takes a turn to the north-northwest and approaches the east coast of the state's peninsula by Friday, the National Hurricane Center said.
Scott pleaded with residents to follow evacuation orders.
"Do not surf. Do not go on the beach. This will kill you," he said at a press conference Thursday. "There is no reason not to leave."
Scott warned Floridians that projected winds of 100 to 150 mph will destroy houses and "millions will lose power, possibly for a long period of time."
"My goal is to make sure everyone is prepared," he said, telling residents to fill up on gas and supplies now. "Evacuate, evacuate, evacuate."
The National Hurricane Center extended the hurricane warning Thursday northward to Altamaha Sound in Georgia, while a watch was put into effect as far north as South Carolina's South Santee River.
"Storm surges are going to go much further inland than people realize, and that's a lot of water all at once. The winds are going to be incredibly high, and the rain is what we're concerned about," South Carolina Gov. Nikki Haley said.
The projected path of the storm, according to the National Hurricane Center:
If it makes landfall, Matthew would be the first major hurricane — Category 3 or higher — to hit the U.S. mainland since Wilma in 2005.
Regardless of whether it's a direct hit, Scott said the impact on Florida "will be catastrophic."
Tropical storm systems typically diminish as they interact with land, but Matthew has stubbornly refused to weaken significantly — not when it slammed first into Haiti, and only slightly when it passed over a sparsely populated area of Cuba.
That's because Atlantic hurricanes usually veer out to sea, thanks to low pressure over the ocean in late summer and early autumn. But the National Weather Service said high pressure has persisted over the western Atlantic and the East Coast in the recent days — trapping Matthew close to the coast and the warm waters of the Caribbean.
South Carolina officials said Wednesday evening that more than 250,000 people had been evacuated from Charleston and other coastal areas — packing westbound traffic on Interstate 26 as motorists headed west, where they found gas hard to get, stores sold out of essential supplies and hotels at capacity.
One man got so frustrated by the traffic that he fired shots at Moncks Corner police officers in Berkeley County, S.C., Wednesday afternoon, the county sheriff's office said.
Lucas Felkel, 35, died Wednesday evening at Trident Medical Center after a deputy returned fire and shot him, the sheriff's office said. No officers or deputies were injured.
Two men were also reported injured in Broward County, Florida, in accidents as they tried to reinforce their homes.
A 56-year-old Weston man suffered non-life-threatening injuries when his aluminum shutters fell on him Wednesday morning, said Mike Jachles, a spokesman for the Broward County Sheriff's Office.
And another man was airlifted to Broward Health Medical Center with undisclosed injuries after he fell 20 feet from a ladder while putting up shutters Wednesday night at his home in the Weston subdivision of Savannah, Jachles said.