Packing winds of up to 220 km/h (140 mph) late Monday, Florence was expected to further strengthen and become "an extremely risky major hurricane" by the time in makes landfall in the Carolinas on Thursday, the National Hurricane Center (NHC) said in a 21:00 UTC update.
SC governor Henry McMaster has ordered the evacuation of the entire 187-mile coastline of the Palmetto State, effective at noon on Tuesday, in anticipation of powerful Hurricane Florence approaching the east coast of the United States.
But the National Hurricane Center said Wednesday evening that the storm is expected to bring life-threatening storm surge and rainfall to the Carolinas as it approaches the coast Thursday and Friday.
South Carolina Gov. Henry McMaster ordered a mandatory evacuation of all eight counties on the coast on Monday, The State newspaper in Columbia reported. Hurricane Florence is large in size.
Florence is "rapidly strengthening", with maximum sustained winds increasing to 170km/h, making it a category 2 storm, the second-weakest on the five-level Saffir-Simpson hurricane scale. All of those states have declared a state of emergency. Also, looking like a direct hit on North Carolina, South Carolina and Virginia.
Hurricane Florence is packing maximum sustained winds of 140 miles per hour and higher gusts on Tuesday morning. She said it was built in 2009 in Buxton, North Carolina, up on a ridge, and made to withstand a hurricane.
The storm's path put a corridor of more than 10 million people in the crosshairs Wednesday as it closed in on the Carolinas, uncertainty over its projected path spreading worry across a widening swath of the Southeast. Hurricane Helene is gaining strength behind Isaac and has reached wind speeds of more than 105 miles per hour.
The Beaufort County Sheriff's Office has not announced any road blocks ahead of Hurricane Florence as of Monday afternoon.
The storm's path could change, though the National Weather Service gets more certain of its forecast as the window to landfall shortens.
Two other storms were spinning in the Atlantic.
"We want to make sure that we get the best data going to the National Hurricane Center. and to emergency managers and to the media so we can get people out of the way", Flaherty said.
While evacuation orders are issued by states as a protective action in disaster events such as hurricanes and wildfires, they are sometimes ignored by people - whether it's because they didn't believe the warnings, didn't have the financial means or refused to abandon friends, family or pets.
Their entire neighborhood evacuated in Wilmington, North Carolina, David and Janelle Garrigus planned to ride out Florence at their daughter's one-bedroom apartment in Charlotte.
He wrote: "My people just informed me that this is one of the worst storms to hit the East Coast in many years".
"This storm is going to be a direct hit on our coast", said Jeff Byard, associate administrator for response and recovery at the Federal Emergency Management Agency.
The Atlantic hurricane season officially began June 1, but cooler water and higher wind shear - winds moving at different speeds and directions - early in the season are less than ideal for tropical systems to gain and maintain strength.