Downgraded to a tropical depression, Florence slowly crawled over South and North Carolina, dumping heavy rains on already flood-swollen river basins that authorities warned could bring more death and destruction.
"The storm has never been more risky than it is now", North Carolina's emergency management office said on Twitter, quoting Governor Roy Cooper.
Up to 6 more inches of rain could fall in parts of North Carolina and Virginia from Sunday evening to Tuesday evening, forecasters said.
Downgraded to a Tropical Storm, its core is now drifting westward over SC, threatening more flash floods and major river flooding. Six people died in SC, including four in vehicle accidents and two from carbon monoxide from a portable generator.
The death toll attributed to Florence stands at 17, including 11 in North Carolina and six in SC.
More than 15,000 people were staying in 150 emergency shelters in North Carolina on Sunday. Police guarded the door of one store, and only 10 people were allowed inside at a time.
The woman had driven around barricades to get on a closed road, the sheriff's office in Union County, near North Carolina's border with SC, said on Facebook. Nor is it clear whether efforts to drain waste-processing facilities for North Carolina's massive hog industry succeeded before rainfall that reached 40 inches in places.
Florence was a tropical depression on Monday with maximum sustained winds of 45 kilometres per hour as it headed through Virginia and towards New England.
On a flooded road near New Bern, Bryan Moore and his nephew Logan made a decision to go swimming in the floodwaters after having spent days at home without electricity or running water.
Record flooding was also reported at Little River in Manchester, North Carolina, which had the highest flood level in the region, and the only river to have a water level above 30 feet as of Monday morning.More news: My Brexit plan or crash out of European Union , says Theresa May
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Meanwhile, the city of Wilmington had been largely cut off from the rest of North Carolina by rising floodwaters from Florence.
"It's awful", said Mitch Colvin, the mayor of Fayetteville, North Carolina, in the eastern part of the state, where the rising Cape Fear River was expected to swamp bridges and cut his city in two. The counties most severely affected by Florence are major farming areas, with some barely above sea level, said Professor Mark Sobsey of the environmental sciences department at the University of North Carolina at Chapel Hill.
Thousands of people were ordered to evacuate homes along rivers. As the storm "begins to finally recede, they will kick into an even higher gear".
Yet one family riding out the storm on the outskirts of Lumberton said they're not budging. People have already died, and were it not for the heroic actions of hundreds of volunteers, more lives would be in peril.
► At least 18 people are dead as Florence batters the Carolinas. The flooding could presist for several weeks in some areas.
The industrial-scale farms contain vast pits of animal feces and urine that can pose a significant pollution threat if they are breached or inundated by floodwaters.
"The floodwaters were rising so I figured I better get out of there", he said.
Near the flooded-out town of New Bern, where about 455 people had to be rescued from the swirling flood waters, water completely surrounded churches, businesses and homes.
"I only just had the roof repaired from (Hurricane) Matthew two years ago", another resident told me.