The severity of Hurricane Florence, a Category 4 storm, is intensifying and triggering hurricane warnings along the coasts of the Carolinas, the National Hurricane Center announced in its 5 a.m. Wednesday update.
The National Hurricane Center said the hurricane's peak winds have decreased slightly to 125 mph but the size of the wind field has increased to outwards of 70 miles from the center.
A view of Hurricane Florence from the International Space Station.
"Dangerous Florence", as the official update calls it, is highly likely to bring with it life-threatening storm surges and catastrophic flash flooding, and damaging hurricane-force winds across vast stretches of SC and North Carolina.
"People need to leave now before they can't", North Carolina Gov. Roy Cooper said.
Beaufort County officials said they were prepared for the worst, including a mandatory evacuation and lane reversals.
The heavy rain expected from Hurricane Florence could flood hog manure pits, coal ash dumps and other industrial sites in North Carolina, creating a noxious witches' brew of waste that might wash into homes and threaten drinking water supplies.
He cited forecasts showing Florence was likely to stall over North Carolina, "bringing days and days of rain".
Swell from Florence continues into Friday.
More than 1.5 million people have been ordered to evacuate along 300 miles of coastline.
Faced with new forecasts that showed a more southerly threat, Georgia's governor joined his counterparts in Virginia and North and SC in declaring a state of emergency, and some residents who had thought they were safely out of range boarded up their homes.
Updated NHC forecasts showed the storm lingering near the coast, bringing days of heavy rains that could bring intense inland flooding from SC, where some areas could see as much as one metre of rain, to Virginia. Rather than pushing up toward western Virginia, the storm's center is now predicted to move across eastern SC on Friday night and Saturday.
Tropical disturbance Invest 95L as of Wednesday morning.
Rain measured in feet is "looking likely", he said.
"It's the most deadly part of the hurricane that comes in".
Melody Rawson evacuated her first-floor apartment in Myrtle Beach and arrived at Atlanta Motor Speedway in Hampton, Georgia, to camp for free with three other adults, her disabled son, two dogs and a pet bird.
On Wednesday, McMaster said that emergency lane reversals - using all lanes of I-26 out of Charleston and Highway 501 near Myrtle Beach for westbound traffic - will cease on Thursday, two days after the measure was instituted.
Calling on residents to follow evacuation orders declared by state and local officials, Byard said the hit by hurricane would not be a "glancing blow", but rather "a Mike Tyson punch to the Carolina coast".
With South Carolina's beach towns more in the bull's-eye because of the shifting forecast, OH tourists Chris and Nicole Roland put off their departure from North Myrtle Beach to get the maximum amount of time on the sand.
Abigail Darlington, covers the city of Charleston for the South Carolina Post and Courier.