US President Donald Trump has issued a disaster declaration for North Carolina as officials warn the state could experience its most severe flooding ever.
The death toll from the hurricane-turned-tropical storm has climbed to at least seven.
A day after Florence blew ashore in North Carolina with 90 mph winds, more than 2ft of rain had fallen in places, with forecasters saying there could be an additional one-and-a-half feet by the end of the weekend.
Rivers and creeks rose towards historic levels, threatening flash flooding that could devastate communities and endanger dams, roads and bridges.
“I cannot overstate it: Floodwaters are rising, and if you aren’t watching for them you are risking your life,” the state’s governor Roy Cooper said.
In its initial onslaught along the coast, Florence buckled buildings, deluged entire communities and knocked out power to more than 870,000 homes and businesses.
But the storm was shaping up as a two-part disaster, with the second stage consisting of inland flooding, caused by rainwater working its way into rivers and streams.
The dead included a mother and baby killed when a tree fell on a house in Wilmington, North Carolina. South Carolina recorded its first death from the storm when officials said a 61-year-old woman was killed when her vehicle hit a tree that had fallen across a highway.
Officials in North Carolina’s Harnett County, about 90 miles inland, urged residents of about 1,100 homes to evacuate because the Lower Little River was rising toward record levels.
In New Bern, along the coast, aerial photos show homes completely surrounded by water, with rescuers using inflatable boats to reach people. More than 360 people have been carried to safety since Thursday night amid rising waters.
With the eye of Florence stalled near the coast, the half of the storm still out over the Atlantic continued to collect warm ocean water and dump it on land.