The massive hurricane is moving slowly, unleashing extra havoc as it hovers over the region, including deadly storm surge and flooding rains.
The storm surge has already put some communities underwater.
Early Saturday, approximately 20 people were rescued near Marine Corps Base Camp Lejeune, in Jacksonville, North Carolina, by military officials and delivered to the Piney Green Volunteer Fire Department before being transferred to Onslow County shelters. Roads in its vicinity were flooded as well.
Utility crews worked to restore electricity even as flood waters inundated whole communities.
The monster storm has claimed five lives, sent more than 22,000 into emergency shelters, and knocked out power to thousands of homes.
Wilmington Police have confirmed that a mother and infant were killed when a tree fell on their home.
In Wilmington, near where the eye of the hurricane touched down, trees and power lines were down and many windows had been broken.
"The fact that there haven't been more deaths and damage is incredible and a blessing", said Rebekah Roth, walking around Wilmington's Winoca Terrace neighborhood.
Hurricane-force winds extended 80 miles (130 kilometers) from its center, and tropical-storm-force winds reached out to 195 miles (315 kilometers). More than a dozen major rivers in the Carolinas and southern Virginia are forecast by the National Weather Service to reach flood stage, and some - including the Neuse, Pamlico, Lumber, Waccamaw, Northeast Cape Fear and the Pee Dee rivers - are expected to set flood records.
"North Carolina Governor Roy Cooper warned in a briefing Saturday morning that more people in the state are in danger now than when Florence made landfall there on Friday". One team from Maryland helped with about 40 rescues in New Bern starting Thursday, member Mitchell Rusland said. Fort Bragg, a sprawling US Army base, is just west of Fayetteville.
Florence is expected to dump several feet of rain on the Carolinas as she makes a slow push inland over the next few days. The storm is expected to turn west and then north moving through the Carolinas and the Ohio Valley by Monday, the NHC said early on Saturday.
Almost 300,000 customers in North Carolina were meanwhile reported to be without power as the outer band of the storm approached.
On Thursday, Florence was a Category 3 hurricane on the five-step Saffir-Simpson scale with 193km.
The hurricane hit the coast around 7:15 a.m. ET, after being downgraded from a Category 4 to a Category 1 storm the day before.
More than 485,000 homes and businesses were without power in North and SC early on Friday, utility officials said.
"Great job FEMA, First Responders and Law Enforcement - not easy, very unsafe, tremendous talent".
In Fayetteville in North Carolina, officials warned people living by swollen rivers that the worst was yet to come.
Zaytoun said he didn't leave his home because he knew he wouldn't have been able to get back to it once the flooding began.
"Our friend behind our old house, they have gators swimming in the water".
A disaster has been declared by US President Donald Trump in eight counties in North Carolina - a move that will help free up federal funding for recovery efforts. At least 1 million people were ordered to evacuate along the coast.