"It's been a cold winter," said Keith Stellman, meteorologist in charge at the National Weather Service in Atlanta/Peachtree City, noting that Wednesday's likely high temperature -- 28 or 29 degrees -- was about 20 degrees below normal.
Forecasters did not predict a heavy snowfall -- up to 2 inches in Alabama, where Gov. Kay Ivey declared a state of emergency and activated the National Guard. Dozens of school systems across the state closed, and businesses and government offices shut down in preparation for the storm.
"This winter storm could be debilitating to the state for a couple of days due to icy conditions," Brian Hastings, director of the Alabama Emergency Management Agency, said in a statement. He urged Alabamians to closely monitor weather forecasts and get off roads before the first flakes of snow touched the ground.
By noon, officials in Limestone County, just east of Huntsville in northern Alabama, reported that all roads -- apart from those in the city of Athens -- were impassable.
Residents were not used to driving in such treacherous conditions, said Daphne Ellison, an emergency management officer in Limestone County, noting the weather had caused multiple traffic pileups and accidents.
"Oh, my goodness, people just sliding off the roads," she said. "You know how it is. People don't know how to slow down. They're just not paying attention."
Ellison, expressing frustration that people insisted on driving, added, "It's rough out there. We're not used to 6-degree weather, but I think people get cabin fever and don't want to stay in the house."
In Louisiana, the National Weather Service in New Orleans/Baton Rouge expanded its winter weather advisory Tuesday to include locations as far southeast as Houma and metro New Orleans. In the Shreveport area, both lanes of Interstate 49 were closed early Tuesday. In Kentucky, all southbound lanes of Interstate 65 were closed Tuesday morning after multiple people were injured in a collision involving a Greyhound bus, two commercial vehicles and two passenger vehicles.
In Texas, the weather was so cold that Gov. Greg Abbott postponed an event in Arlington to announce his plan to rein in rising property taxes in the state. In a statement, he warned of "life-threatening situations," and added, "I urge all Texans to exercise extreme caution in these hazardous conditions."
Conservationists sprang to the aid of sea turtles in frozen waters off the Texas coast, said Melissa Angel, a spokeswoman for the Turtle Island Restoration Network. The California-based nonprofit has an office in Galveston, and volunteers already helped rescue about 2,500 turtles during a cold snap earlier this month.