North Carolina corrections officials said more than 3,000 people were relocated from adult prisons and juvenile centres in the path of Florence, and more than 300 county prisoners were transferred to state facilities.
The National Hurricane Center (NHC) downgraded it to a tropical storm on Friday, but warned it would dump as much as 30 to 40 inches (76-102 cm) of rain on the southeastern coast of North Carolina and part of northeastern SC.
Georgia joined four other coastal states issuing an emergency declaration as forecasts showed Florence dumping historic amounts of torrential rain on the southern state.
The storm is expected to slow down, stall and then perhaps wander just off the Carolina shore as it nears the coast Thursday, Friday and Saturday. At least 51 inches of rain were measured by a gauge outside of Houston, a new record for rainfall brought to a single area by a storm in the U.S.
Mandatory evacuation orders have been placed for millions of people along the coast with more to possibly come as the path of the storm becomes more apparent.
"Get out of its way, don't play games with it, it's a big one, maybe as big as they've seen", Trump said.
"We'll handle it. We're ready".
At the White House, President Donald Trump both touted the government's readiness and urged people to get out of the way of Florence.
More than 634,000 homes and businesses were without power in North and SC early on Friday, utility officials said.
Duke Energy, the nation's No. 2 power company, said Florence could knock out electricity to three-quarters of its 4 million customers in the Carolinas, and outages could last for weeks.
Whenever a tropical cyclone makes landfall, it comes with powerful storm surge, hurricane and tropical-storm force winds, isolated tornadoes and very heavy rainfall. After a Friday landfall near Cape Fear, N.C., the storm is expected to drift slowly west, battering the Carolinas through the weekend.
"The state is mobilising all available resources to ensure public safety", Deal said.
Small said the precautions have worked in previous hurricanes, but he said he remained wary of the flooding potential from the storm with the same name as his town. Forecasters said Florence is expected to blow ashore late Thursday or early Friday, even as President Donald Trump has declared states of emergency for North and SC and Virginia, opening the way for federal aid.
Amtrak canceled its passenger rail service south of Washington, D.C., and there were almost 600 cancellations of flights arriving or departing from major airports in the Carolinas.
"All my staff are gone", Thompson said. Some of those who stayed went to shelters while others stuck it out in their homes.Maysie Baumgardner, 7, and her family sheltered at the Hotel Ballast in downtown Wilmington as Florence filled the streets with floodwaters. "You can't stop Mother Nature".
SC ordered the mandatory evacuation of one million coastal residents while North Carolina ordered an evacuation of the Outer Banks, barrier islands that are a popular tourist destination. Those pipelines carry fuel from the Gulf Coast to much of the eastern United States.
In the city of New Bern, one of the hardest hit areas in North Carolina, more than 300 people were trapped in cars, on roofs and in their attics overnight after over 10 feet of storm surge flooded the river-front city.