NEW BERN, N.C. -- The Marines, the Coast Guard, civilian crews and volunteers used helicopters, boats and heavy-duty vehicles Saturday to rescue hundreds of people trapped by Florence's onslaught, even as North Carolina braced for what could be the next stage of the disaster: widespread, catastrophic flooding inland.

The death toll from the hurricane-turned-tropical storm climbed to 11.

A day after blowing ashore with 90 mph (145 kph) winds, Florence practically parked itself over land all day long and poured on the rain. With rivers swelling toward record levels, thousands of people were ordered to evacuate for fear the next few days could bring the most destructive round of flooding in North Carolina history.

More than 2 feet (60 centimetres) of rain had fallen in places, and the drenching went on and on, with forecasters saying there could be an additional 1 1/2 feet (45 centimetres) by the end of the weekend.

"I cannot overstate it: Floodwaters are rising, and if you aren't watching for them, you are risking your life," Gov. Roy Cooper said.

As of 8 p.m., Florence was centred about 65 miles (100 kilometres) east-southeast of Columbia, the South Carolina capital, crawling west at 2 mph (4 kph) -- not even as fast as a person walking. Its winds were down to 45 mph (75 kph). But with half of the storm still out over the Atlantic, Florence continued to collect warm ocean water and dump it on land.

In its initial onslaught along the coast, Florence buckled buildings, deluged entire communities and knocked out power to more than 900,000 homes and businesses. But the storm was shaping up as a two-part disaster, with the second, delayed stage triggered by rainwater working its way into rivers and streams. The flash flooding could devastate communities and endanger dams, roads and bridges.

Authorities ordered the immediate evacuation of up to 7,500 people living within a mile (1.6 kilometres) of a stretch of the Cape Fear River and the Little River, about 100 miles (160 kilometres) from the coast. The evacuation zone included part of the city of Fayetteville, population 200,000.

And on Saturday evening, Duke Energy disclosed that heavy rains had caused a slope to collapse at a coal ash landfill at a closed power station outside Wilmington, North Carolina. Duke spokeswoman Paige Sheehan said about 2,000 cubic yards (1,530 cubic meters) of ash were displaced at the Sutton Plant and that contaminated storm water likely flowed into the plant's cooling pond.

The company hasn't yet determined i whether any contamination may have flowed into the Cape Fear River. Sutton was retired in 2013 and the company has been excavating ash to remove to safer lined landfills. The grey ash left behind when coal is burned contains toxic heavy metals, including lead and arsenic.

Elsewhere, officials in Harnett County urged residents of about 1,100 homes to clear out because the Lower Little River was rising toward record levels.

One potential road out was blocked as flooding forced the shutdown of a 16-mile (26-kilometre) stretch of Interstate 95, the main highway along the Eastern Seaboard.

In New Bern , along the coast, homes were completely surrounded by water, and rescuers used inflatable boats to reach people.

Kevin Knox and his family were rescued from their flooded brick home with the help of Army Sgt. Johan Mackie, part of a team using a phone app to locate people in distress. Mackie rode in a boat through a flooded neighbourhood, navigating through trees and past a fencepost to get to the Knox house.

"Amazing. They did awesome," said Knox, who was stranded with seven others, including a boy who was carried out in a life vest. "If not, we'd be stuck upstairs for the next ... how long? I have no idea."

New Bern spokeswoman Colleen Roberts said 455 people in all were rescued in the town of 30,000 residents without any serious injuries or deaths. But thousands of buildings were damaged in destruction Roberts called "heart-wrenching."

Across the Trent River from New Bern, Jerry and Jan Andrews returned home after evacuating to find carp flopping in their backyard near the porch stairs.

Coast Guard helicopters were taking off across the street to rescue stranded people from rooftops and swamped cars. Coast Guard members said choppers had made about 50 rescues in and around New Bern and Jacksonville as of noon.

Marines rescued about 20 civilians from floodwaters near Camp Lejeune, using Humvees and amphibious assault vehicles, the base reported.

In Lumberton, about 80 miles (130 kilometres) inland, Jackie and Quinton Washington watched water filling both their front and back yards near the Lumber River . Hurricane Matthew sent more than 5 feet (1.5 metres) of water into their home in 2016, and the couple feared Florence would run them out again.

"If it goes up to my front step, I have to get out," Quinton Washington said.

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, with officials saying a 61-year-old woman was killed when her car hit a tree that had fallen across a highway.

Three died in one inland county, Duplin, because of water on roads and flash floods, the sheriff's office said. A husband and wife died in a house fire linked to the storm, officials said, and an 81-year-old man died after falling and hitting his head while packing to evacuate.

In Washington, President Donald Trump was briefed by telephone Saturday on Florence's impact. The White House released a photograph showing Trump seated at a desk with a phone to his ear and Vice-President Mike Pence standing nearby. Later, Trump tweeted his condolences, writing, "Deepest sympathies and warmth go out to the families and friends of the victims. May God be with them!"

Retired Marine Garland King and his wife, Katherine, evacuated their home in New Bern on Friday and returned Saturday, sharing a kiss and joining hands as they drew near their house.

"It was tough. Wobbling. I was looking for water moccasins to hit me at any time," he said.

They finally made it, and found a soggy, stinking mess.

"The carpets. The floors. Everything is soaking wet," Katherine King said. "We're going to have to redo the whole inside."

The National Hurricane Center said Florence broke a North Carolina rainfall record that had stood for almost 20 years: Preliminary reports showed Swansboro got more than 30 inches (75 centimetres) and counting, obliterating the mark set in 1999, when Hurricane Floyd dropped just over 24 inches (60 centimetres) on the state.

As of noon, Emerald Isle had more than 23 inches (58 centimetres) of rain, and Wilmington and Goldsboro had about a foot (30 centimetres). North Myrtle Beach, South Carolina, had around 7 inches (18 centimetres).

Stream gauges across the region showed water levels rising steadily, with forecasts calling for rivers to crest Sunday and Monday at or near record levels. The Little River, the Cape Fear, the Lumber, the Neuse, the Waccamaw and the Pee Dee were all projected to rise over their banks, flooding cities and towns.

Forecasters said the storm will eventually break up over the southern Appalachians and make a sharp rightward swing to the northeast, its rainy remnants moving into the mid-Atlantic states and New England by the middle of the week.

AP writers Jonathan Drew in Wilmington; Jeffrey Collins in Fork, South Carolina; Emery P. Dalesio in New Bern; Denise Lavoie and Sarah Rankin in Richmond, Virginia; Gary Robertson in Raleigh, North Carolina; Meg Kinnard in Columbia, South Carolina; Seth Borenstein and Michael Biesecker in Washington; Martha Waggoner in Raleigh, North Carolina; Jennifer Kay in Miami; Russ Bynum in Columbia, South Carolina; Pete Iacobelli in Clemson, South Carolina, and Jay Reeves in Atlanta contributed to this report.