Very heavy snow is forecast for the Appalachian Mountains, CNN meteorologist Haley Brink said, with Asheville, North Carolina, and Roanoke, Virginia, predicted to get 12-18 inches.
On Saturday, the governor urged people not to risk travel during the snowstorm, which he reminded residents isn't the same thing as "snow fall".
Governor Ralph Northam declared the emergency Saturday morning, with an effective date of December 7.
"North Carolina is in the cold, icy grip of a mammoth, winter storm", Cooper said.
Being prepared means having up to three days worth of food on-hand and an emergency kit in your vehicle, said North Carolina's emergency management officials on Saturday.More news: House Republicans release Comey interview transcript
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Cooper said crews are working around the clock across North Carolina to clear the roads and help stranded drivers.
"Each night, any snow that melts during the day.it could refreeze", forecaster David Roth told NPR.
The Lubbock Police Department tweeted late Saturday that black ice and freezing fog were beginning to form on areas Interstate 27. "Getting out on risky roads could put your life at risk".
More than 25 million people are under winter weather alerts from Oklahoma through Virginia, and more than 10 million are under a flood threat from the Gulf coast to SC. Cancellations were reported on flights from as far as the Midwest. More than 99,000 were without power in SC, while a total of more than 55,000 outages were reported across Tennessee, Alabama and Georgia.
A wintry storm tearing through the Southeast threatens to keep residents stuck at home as risky driving conditions, canceled flights and power outages could stretch for days. 3 to 7+ inches of snow with some ice is possible in the watch area.
More than 1,000 Sunday flights into and out of North Carolina's Charlotte Douglas International Airport have been canceled, according to flight tracking website FlightAware. This will be especially problematic in parts of the Charleston, South Carolina, area.