South Carolina National Guard soldiers transfer bulk diesel fuel into fuel tanker trucks for distribution in advance of Hurricane Florence, in North Charleston, South Carolina, on September 10, 2018. (U.S. Army National Guard/Sgt. Brian Calhoun/Handout via REUTERS)
Heavy rain in the Washington area over the weekend has already led to flooding in historic Alexandria, Virginia, and the National Weather Service issued a flood watch for part of the Potomac River.
Florence is currently moving west at around 13mph (20kph).
North Carolina Governor Roy Cooper's office said Florence is already being felt along the state's coast, with large sea swells resulting in life-threatening rip currents and surf.
"This is a huge storm," said Robert Woodward, chairman of the Dare County Board of Commissioners, predicting 15 to 20 inches of rain.
"Never have we seen quite this type of a storm approach us."