Wintry storm pounding the Southeast will cause ‘several days of difficult or impossible travel’

Snow covers houses and roads in Lubbock, Texas.

(CNN) — A wintry storm tearing through the Southeast threatens to keep residents stuck at home as dangerous driving conditions, canceled flights and power outages could stretch for days.

“Over 20 million people are under winter weather alerts, over 8 million people are under a flash flood threat, and over 9 million people are under wind advisories,” CNN meteorologist Haley Brink said Sunday.

More than 12 inches of snow will fall Sunday in the southern and central Appalachians, the National Weather Service said. Snowfall could total 12 to 20 inches over the Appalachians and into the Carolinas by Monday, when the storm is expected to move off the coast, the agency said.

“Snowfall amounts in some locations will likely exceed a foot and result in several days of difficult or impossible travel, extended power outages, and downed trees,” the National Weather Service said.

The storm already has knocked out power for more than 216,500 customers in the southeastern US.

Most of the outages are in North Carolina, where 102,383 customers are in the dark. In South Carolina, more than 52,100 customers have lost power. And between Alabama and Georgia, more than 62,000 customers don’t have electricity.

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. The Charlotte airport said it expects scattered cancellations through Monday morning, with the majority expected to be of small, regional planes.

About 80% of flights at Charlotte Douglas, 40% of flights at Raleigh-Durham International Airport and 50% of flights at Piedmont Triad International Airport have been canceled for Sunday, Brink said.

North Carolina gets pummeled with snow

In Durham County, residents typically get about 6 inches of snow over an entire year. But on Sunday morning, they woke up to see 6 inches of snow on the ground.

The Durham County Sheriff’s Office warned drivers by tweeting photos of slick, snow-covered roads and an SUV driver in trouble.

“Our advice to you is unless you absolutely have to go out… #stayhome,” the sheriff’s department said. “Roads are treacherous as this person found out when they tried to drive on Stallings Rd.”

Even before the storm hit, North Carolina authorities declared a statewide emergency. Grocery store shelves were cleared of bread, milk and other staples.

Many churches in the Charlotte area preemptively canceled Sunday services, CNN affiliate WSOC reported, and the city of Charlotte is prepping emergency shelters.

“This storm comes at a time of year when North Carolinians are usually hearing carols about snow, not actually seeing it,” Gov. Roy Cooper said, according to WSOC.

“A winter storm’s not a Christmas carol snow. It’s serious, and you need to take steps now to get your family ready.”

‘Ice is becoming a big problem’ in South Carolina

In South Carolina, a state known for palmettos rather than freezing rain, ice-covered roads are making driving conditions perilous.

“Ice is becoming a big problem. Please stay off the roads,” Greenville County Emergency Management pleaded.

The local National Weather Service office had to adjust its forecast map Sunday after it became clear more ice was expected near Interstate 85.

“We have increased our ice (accumulation) forecast quite a bit along the I-85 corridor,” the NWS Greenville-Spartanburg office said.

And with ice and heavy snow come power outages.

As of 4:30 a.m. Sunday, 2.5 inches of snow had fallen in the Greenville-Spartanburg area.. Half an hour later, the county’s emergency management office said 14,189 customers had lost power.

The storm left a trail of misery in Texas

Before striking the Southeast, this moisture-heavy storm walloped Texas flash flooding along the southern edge of the state and snow and ice in the north.

As the moisture moved eastward, it collided with a high-pressure system over the Ohio Valley that is funneling cold air into the region.

Houston experienced flooding after 4 to 6 inches of rain fell Friday night, with some drivers forced to abandon their cars on major highways, CNN affiliate KTRK reported.

In Lubbock, Texas Tech University rescheduled all Saturday final exams for Sunday.

Parts of the Lubbock were buried under 10 inches of snow — 2 inches more than the city usually gets in a whole year.

“They crushed their yearly average in 24 hours,” CNN meteorologist Ivan Cabrera said.