Many people in Wilmington emerged from their homes for the first time on Saturday morning to scenes of lifted trees and fallen powerlines.
The monster storm could dump drenching rains of up to one meter. He estimated a total of 18 trillion gallons will fall on all affected states.
Forecasters say the combination of a life-threatening storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. That's enough to fill the Chesapeake Bay, or cover the entire state of Texas with almost 4 inches of water.
"This storm will be a marathon vs. a sprint", the National Weather Service said on Twitter.
48 hour radar estimated rainfall totals.
All North Carolina state parks are already closed or will close today and will remain closed through Sunday. "The storm is going to continue its violent grind across our state for days".
The previous record crest was 29 feet set during Hurricane Matthew in 2016.
"Honestly, I'm not sure" why some people refused to follow evacuation orders, David Cotton, county manager for North Carolina's Onslow County, told "Good Morning America" on Saturday.
Hurricane-force winds extended 90 miles (150 kilometers) from its center, and tropical-storm-force winds up to 195 miles (315 kilometers).
Sample said that when he looked outside of his house, which is about 1,000 yards from the beach, he saw the rain pooling up on the street and what looked like storm surge coming up the road. "The house is shaking back and forth much more violently than when the eyewall came through". South Carolina Governor Henry McMaster said the heavy rain could trigger landslides in the west of his state.
Flash-flood emergencies - the most critical category of flood warning - have been in effect for several counties in southeast North Carolina since Friday night.
The region is being pounded with rain from the slow-moving storm, causing the risk of catastrophic flooding.
The NHC said Florence went ashore near Wrightsville Beach, North Carolina, at 7:15 a.m. EDT with estimated maximum winds of 90 miles per hour.
Power outages are widespread, affecting over 740,000 homes and businesses in North Carolina and 163,000 in SC.
The Cape Fear River in Fayetteville, N.C.is forecast to rise an astonishing 45 feet by Tuesday.
It's about the water, not the wind, with Hurricane Florence making an extended stay along the North Carolina coast. And there could be 10 inches (25 cm) in south-western Virginia. That means its torrential rains will be felt harder.
The rest of SC and North Carolina into southwestern Virginia will experience 5 to 10 inches, with isolated totals up to 15 inches.
National Weather Service forecaster Brandon Locklear predicted Florence would drop up to eight months of rain in two or three days. Its westward motion is expected to continue through Saturday.
Storm Florence may have weakened but the full extent of the damage it has wreaked may not become clear for days.
People wait in the rain to enter a Waffle House a day after Hurricane Florence hit the area, on September 15, 2018 in Wilmington, North Carolina. The center was about 20 miles north-northeast of Myrtle Beach. More people now face imminent threat than when the storm was just offshore.