DALLAS (AP) — Snow and icy conditions threatened to paralyze parts of the U.S. South from Texas to Alabama on Thursday, as officials closed schools, canceled or delayed flights and warned residents in some of the worst-hit areas to stay off roads as a winter storm moves east.

Paul Kirkwood, a National Weather Service meteorologist, said the storm sweeping through the Dallas area will create a “swath of snow” as it moves through parts of Arkansas, Louisiana, Alabama, Mississippi, Georgia, Tennessee, Kentucky, North Carolina and South Carolina.

Charles Daniel, a truck driver hauling a 48-foot trailer in south-central Oklahoma on Thursday, said the roads were slushy and slick.

“I have not seen any accidents, but I have seen a couple of people get stuck out on the road and sliding around,” he said. “People do not need to be driving.”

The storm started dumping a mix of sleet and heavy snow Thursday morning in north Texas and Oklahoma, where schools canceled classes for more than 1 million students. Closures also kept students home in Kansas City and Arkansas, while in Virginia, frustrations mounted in the state capital over a boil-water advisory caused by an earlier round of winter storms.

Hundreds of flights were canceled by Thursday morning in Dallas, according to tracking platform FlightAware, with more than 3,100 delays and 2,100 cancellations reported nationally.

The cold snap coincided with rare January wildfires tearing through the Los Angeles area, forcing residents to flee from burning homes through flames, ferocious winds and towering clouds of smoke.

Snow, sleet hammering Texas, Oklahoma

Road crews began treating roads in Arkansas, Oklahoma and Texas ahead of the expected arrival of as much as 7 inches (about 18 centimeters) of snow in some parts of those states. The precipitation early Thursday was mostly wet snow in the Dallas metroplex, with heavier snowfall farther north into Oklahoma, according to the National Weather Service.

Gov. Greg Abbott said the state deployed emergency crews in advance and urged residents to avoid driving in bad weather if possible. In Arkansas, Gov. Sarah Sanders mobilized 140 National Guardsmen to assist State Police with transporting any stranded motorists.

Roads could be slick Friday as 75,000 fans were expected head to AT&T Stadium in Arlington for the college football championship semifinal between Texas and Ohio State in the Cotton Bowl. Arlington spokesperson Susan Shrock said crews will be ready to address any hazardous road conditions.

Southern discomfort

The system was expected to push northeastward by Friday with heavy snow and freezing rain all the way to the Virginia and North Carolina coasts. As much as 8 inches (about 20 centimeters) of snow could fall in parts of Georgia, North Carolina, Tennessee and West Virginia through Saturday, the weather service said.

Georgia Gov. Brian Kemp declared a state of emergency across the state on Thursday as the northern half of the state girded for snow and ice beginning Friday morning. National Weather Service forecasters are warning that snow and ice are likely to accumulate across metro Atlanta, making roadways treacherous and possibly threatening power outages.

Tennessee Emergency Management Agency Director Patrick Sheehan said he expected schools across the state to close Friday, although decisions will be made at the local level. With Memphis forecast to receive up to 6 inches of snow Friday, officials said two warming centers are open 24 hours to provide shelter for people who need to escape the cold. The city is providing transportation to the centers.

The polar vortex of ultra-cold air usually spins around the North Pole, but it sometimes ventures south into the U.S., Europe and Asia. Some experts say such events are happening more frequently, paradoxically, because of a warming world.

A boil-water order for Virginia’s capital

Richmond will remain under the boil-water advisory until at least Friday as officials work to restore the water reservoir system, which malfunctioned after a storm caused a power outage, Mayor Danny Avula said.

The city of more than 200,000 was distributing bottled water at 11 sites and delivering it to older residents and others who are unable to get to those locations, officials said.

“We’ve got families in the city, they don’t have any water,” Gov. Glenn Youngkin said Wednesday. “We’ve got young children where mothers are asking, ‘What do I do about baby formula?’”

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Murphy reported from Oklahoma City. Associated Press reporters Heather Hollingsworth in Kansas City; Charlotte Kramon in Atlanta; Nadia Lathan in Austin, Texas; Ben Finley in Norfolk, Virginia; Andrew DeMillo in Little Rock, Arkansas; Kimberly Chandler in Montgomery, Alabama; John Raby in Cross Lanes, West Virginia; and Dylan Lovan in Louisville, Kentucky.

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Read more of the AP’s climate coverage at http://www.apnews.com/climate-and-environment