After a rare winter storm walloped the South with record snowfall, from the swamps of Louisiana to the beaches in the Carolinas, the region faced a new threat Thursday morning of dangerously icy roads that, in some parts, may not fully melt until the weekend.

Such conditions left officials throughout much of the South echoing the same message: The effects from the storm were not over, and driving remained a hazard on untreated roads still frozen with slippery ice.

While temperatures were expected to briefly rise above freezing in parts of Louisiana, southern Alabama and Mississippi, Georgia, northern Florida and coastal communities in the Carolinas, colder nighttime temperatures would likely cause snow and ice to refreeze on roads. There is also an increased risk of black ice, the slick patches that can form unpredictably and almost invisibly because they blend in with the asphalt.

“Ice is ice, and it will present a hazard to motorists if they’re not prepared,” Richard Bann, a meteorologist with the National Weather Service, said.

The threat is worse in a region that is unaccustomed to severely cold weather, and where snow plows are not regularly well stocked.

The storm was already extremely disruptive in the region earlier this week, with scores of schools canceling classes, airports delaying or canceling flights and travel made nearly impossible. Fueled by a whirling mass of Arctic air, the storm has also killed at least 10 people in Texas, Alabama and Georgia.

And cities received record amounts of snow: Mobile, Ala., reported 7.5 inches; Pensacola, Fla., received 7.6 inches, breaking its three-inch record from 1895; and New Orleans saw eight inches, more than Anchorage got this month.

In North Carolina, where eastern coastal communities received as much as six inches of snow, the State Department of Transportation deployed more than 1,300 trucks to clean roads.

“It is important to remember that below freezing temperatures will remain for the next few days. Any snowfall that does melt will refreeze each evening,” Will Ray, the director of the state’s emergency management office, said.

Several officials and utility companies urged residents to help conserve power.

“We are not out of woods yet,” Baldwin EMC, an electric utility in southern Alabama, said in a post on social media.

In Mobile, a port city on Alabama’s coast, residents’ initial jubilee about the snow has started to morph into concern about travel, as many roads have been deemed impassable.

“The snow has been beautiful and fun, but there could be a lot of problems hiding under all this snow and ice,” Eddie Tyler, the superintendent of the Baldwin County Public Schools system, wrote in a letter to parents after canceling school for the remainder of the week.

In South Carolina, heavy blankets of snow caused several bridges to close, but the State Department of Transportation said that it had not closed any interstates as of Wednesday, a promising sign that major roads would not be chaotic the rest of the week.

In Louisiana, the state’s transportation department said that a major portion of Interstate 10, extending from the state line with Texas to Baton Rouge, La., was closed in both directions on Wednesday night.

The Georgia State Patrol said that it had responded to more than 100 vehicle crashes. In DeKalb County, Ga., more than 100 vehicles were stranded on icy roadways and “obstructing emergency response efforts,” the authorities said.

Progress to clear the roads, officials said, had been slow because of freezing temperatures. Even some fire trucks had become stuck.

“This is a serious situation,” Lorraine Cochran-Johnson, the county’s chief executive, said. “We are asking for everyone’s patience and cooperation as our teams work around the clock to ensure public safety.”