The storm roared ashore under the cover of darkness, pummeling the region with pounding rain, widespread flooding and catastrophic winds.
More ominously, forecasters said the onslaught on the coast would last for hours and hours because Florence had come nearly to a dead halt at just 3 mph (6 kph) as of midday. "But I think we're ready".
Tropical storm-force winds extend outward up to 175 miles (280 kilometers) from its center.
"Some of the rainfall totals we're getting are already adding up to about 14 inches", NHC Director Ken Graham said shortly after 11 a.m. ET. Florence dumped more than 20 inches on Oriental, N.C., the NHC said.
Along the coast, floodwaters have been hitting inland towns near rivers that normally discharge into the ocean. As Cooper said, "There's nowhere for the water to go".
The deadly storm made landfall on the east coast of the U.S. on Friday bringing with it "biblical" flooding on what's been described as a "thousand-year rain event". Across the two states there are some 30,000 people staying in emergency shelters.
The No. 1 mission right now, Cooper said, is to save lives. "These are folks who made a decision to stay and ride out the storm for whatever reason, despite having a mandatory evacuation", city public information officer Colleen Roberts said.
More than 810,000 people lacked power in North Carolina, and another 170,000 outages were reported in SC, according to emergency-management agencies. It came ashore along a mostly boarded-up, emptied-out stretch of coastline.
New Bern assured its residents that additional resources were on their way, including from out of state. "I'm not sure if it's a shift in the wind or low tide - but the water has miraculously disappeared".
"In about four days when all the water comes down from North Carolina, that's when we're going to have a problem".
"I'm anxious about what I might find when I go home, though", she said.
Farther up the coast, in New Bern, about 150 people waited to be rescued from flooding on the Neuse River, WXII-TV reported.
Wilmington was battered by high winds and rising flood water as a pier was smashed by a huge wave. At the city's airport, the wind was gusting at 91 miles per hour.
Zooming out to the full projection, shown above, the core of the storm is slated to enter North Carolina around 2 p.m. ET on Sunday.
Though Florence's shrieking winds diminished from hurricane force as it came ashore, forecasters said the sheer size of the 350-mile-wide storm and its painfully slow progress across North and SC in the coming days could leave much of the region under water. Significant weakening is expected over the weekend.
President TrumpDonald John TrumpTrump stands by tweets questioning Puerto Rico death toll: "NO WAY" Trump pushes back on ex-lawyer putting out book, cites "attorney-client privilege" Wealthiest Republican supporter in OH quits party MORE has approved a disaster declaration for North Carolina as the state deals with Tropical Storm Florence, the White House announced Saturday.
Firefighters in North Carolina took a moment to kneel and pray at the site where a mother and baby were killed by a tree that fell down during Hurricane Florence. Some areas in SC could see rainfall totals of up to 15 inches, forecasters said.
To prepare for this storm, businesses have been boarding up, and supplies have been readied for what is expected to be a large-scale relief operation. The figure for SC was 170,000.
The New Bern Police Department tweeted early Thursday evening "City of New Bern officials are encouraging all residents to shelter in place due to Hurricane Florence".
In an update published at 5:33 a.m. ET on Saturday, the agency said that the storm is now striking SC and has a path through the in-land charted for the next few days. The fear is that during that slow march west, it'll drop torrential rains, flooding low-lying areas and overwhelming rivers.
This landfall has been a long time coming: The hurricane arrived more than two weeks after the National Hurricane Center issued its first advisory for the storm. Its designation then was "potential tropical cyclone six". That advisory came out on August 30, when Florence was developing near the Cabo Verde Islands across the Atlantic.