Gov. Henry McMaster ordered mandatory evacuation of 830,000 people along the entire South Carolina coast starting noon Monday with powerful Hurricane Dorian forecast to rake near the state by midweek.
Counties included in the evacuation order are all or portions of Charleston, Berkeley, Dorchester, Beaufort, Colleton, Jasper, Georgetown and Horry.
The state will reverse lanes on Interstate 26 from Charleston to Columbia and on U.S. 278 from Hilton Head Island starting at noon Monday.
The lane reversals are starting early because traffic from the coast was already expected to be heavy Monday, the end of the Labor Day holiday weekend. Charleston hotels were at 70 percent occupancy over the weekend, state officials said.
"When you add the residents evacuating ... that will create a recipe for gridlock or worse," McMaster said during a news conference from the state's emergency operations center in West Columbia. "We do not want people to be stuck on the highway."
No lane reversals were announced for the Myrtle Beach area.
Schools and government offices will be closed Tuesday in the eight coastal counties under the evacuation orders. They are already closed Monday for Labor Day.
About 200 coastal hospitals, nursing homes and assisted-living centers in those counties will be evacuated. Shelters will open Monday as evacuations start. A list can be found on the state emergency agency website, scemd.org/stay-informed/emergency-shelters. A state-run evacuation hotline also starts Monday at (866) 246-0133.
"With these announcements, we know that we cannot keep everybody happy, but we believe we can keep everyone alive," McMaster said.
McMaster evacuated the entire coast in September when Hurricane Florence struck South Carolina, ordering 760,000 people to leave. An estimated 441,000 people actually evacuated.
The latest evacuations cover all of Charleston and Beaufort counties.
The order covers specific zones in other counties that are established by the state's emergency management agency and published at scemd.org/prepare/know-your-zone.
The order involves: zones B and G of Berkeley County and zone D in Dorchester County, which includes Goose Creek, Summerville and Ladson; zones A and B of Colleton County, which includes Edisto Beach and parts of Walterboro; zone A in Horry and Georgetown counties, areas generally east of U.S. 17; and zone A of Jasper County.
Dorian intensified Sunday becoming a Category 5 storm with maximum winds of up to 185 mph while going over the northern Bahama islands.
The National Hurricane Center's forecast has the storm turning north early Tuesday and barreling just off the Florida coast.
Winds from Dorian are expected to reach South Carolina by Thursday morning. The storm will weaken as it moves north but will remain a hurricane as it passes off the S.C. coast with storm surge possible.
No landfall in South Carolina is forecast.
The eye of the storm is predicted to pass east of Charleston around noon Thursday and could bring up to 10 inches of rain and winds up to 70 mph along the coast. The Midlands could get up to four inches of rain and winds up to 50 mph.
McMaster said he spoke with President Donald Trump on Sunday and asked for a federal emergency declaration that will help reimburse the state for storm-related costs. The governor declared a statewide emergency on Saturday that activated South Carolina's storm emergency plan.
South Carolina has 1,000 National Guard troops, 2,200 transportation employees and 700 state law enforcement officers ready to handle the storm.
State emergency crews have 150,000 sandbags, 10,000 tarps, 500 pallets of ready-to-eat meals and 750 pallets of water ready in a warehouse in Winnsboro.
"This is strictly not just a coastal event," S.C. Emergency Management Division director Kim Stenson said. "Certainly could see inland issues with winds and possibly flooding."
Florence flooded rivers in the Pee Dee more than 100 miles from the coast last year, causing more than $600 million in damage.