The major highways into the Wilmington area, Interstate 40 and USA 74, were not accessible Sunday, officials said.
At the White House, President Donald Trump said nearly 20,000 military personnel and federal workers were deployed to help with the aftermath. "This is a monumental disaster for our state". He ordered that federal aid be used "to supplement state, tribal and local" recovery efforts in the state.
New York Gov. Andrew Cuomo announced his support of North Carolina on Twitter earlier in the week. Parts of I-95 were also closed in SC, along with a number of highways in the eastern portion of the state.
The data comes from the National Inventory of Dams.
North Carolina emergency response officials tweeted that 23 truckloads of military meals and bottled water were delivered overnight to Wilmington, the state's eighth-largest city.
On Monday, President Trump declared a major disaster in SC, listing eight counties: Berkeley, Charleston, Dorchester, Georgetown, Horry, Marion, Orangeburg, and Williamsburg.
About 12,000 customers were without service in Virginia. More dams have been built on numerous rivers that snake through the state, and improved forecasting tools have made it easier to position rescue teams.
Flooding worries increased in West Virginia and Virginia, where roads were closed and power outages were on the rise.
Forecasters say it is especially risky after dark because people trying to escape may not realize how deep flood water is on roads.
Florence has soaking wet North Carolina with yet more rain and officials have warned residents that "the worst is yet to come" from a storm that has killed at least 14 of us, with rivers inland at possibility of flood. In the western Carolinas, specifically areas prone to landslide, the NWS advised that those who live on a mountainside, or a cove at the base of a mountain should be prepared to evacuate ahead of the worst of the storm reaching them.
Officials at the Great Smoky Mountains National Park will begin assessing the impact of Tropical Storm Florence.
"We know that children have been ripped from the lives that they knew, and they're unsure of what the future may hold", Thompson said.
In South Carolina, 40 major roads were closed.
Other roads and facilities have remained open, including the Sugarlands and Oconaluftee visitor centers.
Luis Durban walks with supplies through floodwater caused by Hurricane Florence in Lumberton North Carolina US Sept 16 2018. Reuters
The death toll climbed to 18 as authorities found the body of a 1-year-old boy who was swept away after his mother drove into floodwaters and lost her grip on him while trying to get back to dry land.
Further inland, flooding hit "a number of roads" in Durham County, N.C., Monday morning, the sheriff's department said.
"There's too much going on", he told a news conference.
The woman's auto was swept off the road by the floodwaters, pinning it against a group of trees.
In Anson County, east of Charlotte, a train derailed on Sunday evening, but it wasn't clear whether it was storm-related or if anyone was injured.
The derailment led to at least one road closure.
- A woman who suffered cardiac arrest in Hampstead, in North Carolina's Pender County.
Florence dumped more than 8 trillion gallons (30 trillion liters) of rain on North Carolina, the weather service said.
"As you can tell, they're not listening to me", he said.
The tropical depression continues to produce widespread heavy rains over parts of North Carolina and north-eastern SC into western Virginia and flash flooding will continue over portions of the western mid-Atlantic region, it said. Four people died in SC, including a woman whose vehicle hit a fallen tree.
"The storm has never been more risky than it is right now", North Carolina Governor Roy Cooper said on Sunday.
Residents waited for hours outside stores and restaurants for water and other basic necessities.
Police guarded the door of another store and only 10 people were allowed inside at a time.