North Carolina Governor Roy Cooper described the hurricane as likely to "continue its violent grind for days" and described the severity of the downfalls as a "1,000 year event".
Donald Trump has issued a disaster declaration for North Carolina as Tropical Storm Florence continues to dump an "epic" amount of rainfall on the U.S. state.
Florence peaked at a terrifying Category 4 with top winds of 140 mph over warm ocean water before making landfall as a Category 1 hurricane at 7:15 a.m.at Wrightsville Beach, a few miles east of Wilmington and not far from the SC line.
Hurricane-force winds extended 90 miles (150 kilometers) from its center, and tropical-storm-force winds up to 195 miles (315 kilometers).
The National Hurricane Center downgraded it to a tropical storm on Friday afternoon, but warned that life-threatening storm surges - in which water is pushed by a storm over land that would normally be dry - and catastrophic freshwater flooding were still expected.
This story will be updated with additional information momentarily.
Florence already has proven deadly with its almost nonstop rain, surging seawater and howling winds, and the threat is days from ending as remnants of the once major hurricane slowly creep inland across the Carolinas.
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.
"The water is rising fast everywhere, even in places that don't typically flood", he said.
That's just the number of customers without power in the Carolinas. "I've never seen the water as high as it came". By 2 p.m., more than 658,000 customers were without power across North Carolina, and the Triangle had begun to experience outages.
The dead included a mother and baby killed when a tree fell on a house in Wilmington, North Carolina.
As 645-kilometre-wide Florence pounded away at the coast with torrential downpours and surging seas, rescue crews used boats to reach more than 360 people besieged by rising waters in New Bern, while many of their neighbours awaited help. They had heeded officials' warnings that the storm was treacherous, with record-setting rains and storm surges not seen in North Carolina in decades. Its surge could cover all but a sliver of the Carolina coast under as much as 11 feet (3.4 meters) of ocean water, and days of downpours could unload more than 3 feet (0.9 meters) of rain, touching off severe flooding.
Florence's eye made landfall over the Wrightsville Beach water tower about 7:15 a.m. Friday, according to the National Weather Service (NWS) office in Wilmington.
A man sits on a park bench in a flooded park as the Cape Fear River rises above its usual height in Wilmington, N.C., on Friday.
Members of Onslow County emergency look to see if a passenger was still in a vehicle that was overtaken by flooding on US Route 17 outside of Jacksonville, North Carolina.