Also, a 77-year-old man was apparently knocked down by the wind and died after going out to check on his hunting dogs, and a man was electrocuted while trying to connect extension cords in the rain, authorities said.
Florence approached the North Carolina coast as a Category 2 storm with a diameter of around 500 miles, but has since been downgraded to a Category 1.
The NHC said in its 2 p.m. ET update that Florence is a Category 2 storm, but it noted that the storm is quite large in diameter.
Florence's top winds were clocked on Thursday at 100 miles per hour (170 km per hour) as it churned in the Atlantic Ocean, down from a peak of 140 mph (224 kph) earlier this week when it was classified a Category 4 storm.
The National Weather Service's Advanced Hydrologic Prediction Service is predicting "Major Flooding", its most severe classification, from south of the Pamlico Sound in North Carolina, to as as far south as the Waccamaw River near Myrtle Beach, SC. The town of Oriental, North Carolina, got more than 20 inches of rain just a few hours into the deluge. One person even said "It takes the kids minds off of it at least". Duke Energy owns six nuclear plants in the hurricane's path, and a spokesman told Reuters the Brunswick plant near Wilmington would be temporarily shut before the hurricane hit.
Many thousand more power customers were without electricity in northeastern South Carolina Friday night.
As of 11 a.m. EDT, Florence was centred about 230km southeast of Wilmington, its forward movement slowed to 17km/h. The storm is then expected to turn westward and then northward through the Carolinas and to the Ohio Valley by Monday, the NHC said.
Meteorologist say conditions will deteriorate throughout the day Friday.
North Carolina Governor Roy Cooper told a news conference, that a "historic storm" would unleash rains and floods that would inundate nearly the entire state.
"There is going to be a lot of rain".
The worst storm surge comes in with a hurricane's eye, and it arrives "with a lot of debris to batter you, and it's not particularly survivable", Masters said.
Surges up to 4 m could inundate Cape Fear, North Carolina to Cape Lookout, North Carolina, with smaller surges ranging from half a meter to 3 m in coastal areas from Edisto Beach, South Carolina to coastal areas extending north into North Carolina. The rainfall will produce life-threatening flash flooding in Virginia and the Carolinas.
About 800 flights in the region were canceled ahead of the storm, CNN reported.
About 10 million people could be affected by the storm.
Officials in several states have declared states of emergency, including in the Carolinas, Georgia, Virginia and Maryland, where coastal areas are still recovering from summer storms.
The White House on Saturday said President Donald Trump had approved making federal funding available in some counties.
The National Hurricane Centre (NHC) says that despite the gradual lowering in wind strength, the storm remains extremely unsafe because of the high volume of rainfall and storm surges predicted.
Florence is now moving to the northwest at 17 km per hour.
A hurricane warning is in effect for South Santee River, SC, north to Duck, NC, and the Albemarle and Pamlico Sounds. Storm surge invades rivers and estuaries, too. And newly formed Subtropical Storm Joyce is not expected to threaten land soon.
Tropical depression: A tropical cyclone in which the maximum sustained surface wind speed is 38 miles per hour.
Tropical Storm Isaac is also moving westward across the eastern Caribbean. This implies that water, even more so than wind, is the most unsafe element of a major storm.
Near Hawaii, Post-Tropical Cyclone Olivia is blowing with winds of over 50 km/h, but it's moving away from the islands.
Hurricane Watch: An announcement that sustained winds of 74 miles per hour or higher are possible within the specified area in association with a tropical cyclone.