Roads and intersections on North Carolina's Outer Banks barrier islands were already inundated with water. By 5 p.m., it was about 50 miles west-southwest of Wilmington, and the wind had dropped to 70 mph.
The National Hurricane Center said Florence was forecast to keep moving farther inland across the Carolinas through the weekend before turning toward the central Appalachian Mountains early next week.
The now Category 1 storm's intensity diminished as it neared land, with winds dropping to 135 km/h by nightfall.
Will Epperson, a 36-year-old golf course assistant superintendent, said he and his wife had planned to ride out the storm at their home in Hampstead, North Carolina, but then reconsidered.
Florence, a strong Category 1 storm with maximum sustained winds of 90 miles per hour, is causing life-threatening storm surges and pounding the coast with hurricane-force winds, the advisory said.
More ominously, forecasters said the onslaught would last for hours and hours because Florence was barely creeping along at 6 mph (9 kph) and still drawing energy from the ocean.
The flooding caused by the storm surge and heavy rain will take days or weeks to subside.
On the mainland in New Bern, next to the Neuse River, authorities said more than 100 people had to be saved from floods and that the downtown area was underwater.More news: As Hurricane Florence Makes Landfall, Trump Tweets Support to First Responders
Nearly 20,000 people had taken refuge in 157 emergency shelters, Cooper said.
"A basketball sized hole was found in a corner room by an Officer", officials said.
A pet dog licked Johan Mackie's face after he helped rescue Kevin Knox's family from their flooded brick home. Florence's landfall - when the center of the eye reaches land - is likely to happen mid- to late morning Friday, CNN forecasters said.
"In a matter of seconds, my house was flooded up to the waist, and now it is to the chest", said Peggy Perry, who along with three relatives, was trapped early Friday in her New Bern home. Roberts said numerous residents live near the Neuse and Trent rivers.
Tropical Storm Florence is still posing life-threatening surges in portions of North and SC.
Flock said the back end of the storm, when it does arrive, is not expected to be as strong, so the area could avoid catastrophic wind damage and storm surges. Emerald Isle is about 84 miles (135 kilometers) north of Wilmington. As the slow-moving storm moves over the Carolinas, it could pummel towns with more than 3 feet of rainwater.More news: Mother, infant, among several killed by Hurricane Florence
With rivers rising toward record levels, thousands of people were ordered evacuated for fear the next few days could bring the most destructive round of flooding in North Carolina history.
"This rainfall will produce catastrophic flash flooding and prolonged significant river flooding", the NHC said.
Forecasters warned of catastrophic flooding and other mayhem from the monster storm, which is only Category 1 but physically sprawling and unsafe.
North Carolina Gov. Roy Cooper called Florence an "uninvited brute" that could wipe out entire communities as it grinds across the state.
As of 2 am local time, Florence was centered about 55 kilometers east of Wilmington, North Carolina.
Millions were asked to evacuate the Carolina coasts as Florence approached this week.
A day after blowing ashore with 90 miles per hour (145 kph) winds, Florence practically parked itself over land all day long and poured on the rain. Its surge could cover all but a sliver of the Carolina coast under as much as 11 feet (3.4 metres) of ocean water, and days of downpours could unload more than 3 feet (0.9 metres) of rain, touching off severe flooding.More news: Gary Neville hits back at dig from Jürgen Klopp on Twitter