Schools shut down or switched to online classes Thursday and road crews got ready for a bitter blast as forecasters said north Alabama was in store for frigid temperatures and a second round of frozen precipitation this week.

More than two dozen school systems in the Tennessee Valley altered schedules because of an approaching storm the National Weather Service said could dump 1 inch of show and coat roads, trees and power lines with ice, but forecasters later said the initial threat may have passed because most precipitation ended before temperatures sank below freezing.

Still, winds combined with temperatures in the teens will make it feel like the single digits overnight, the National Weather Service said, and icy spots that could make driving dangerous were still possible on roads, particularly bridges and overpasses.

David Smith, director of the Colbert County Emergency Management Agency, said the potential for ice was the biggest concern.

“If we get anything on the trees and it brings down power lines, that’ll be an issue, too, that we don’t need,” he told a news briefing.

Just how far south the snow or ice reaches depends on how quickly freezing temperatures invade the Deep South, but the weather service said the main threat was north of the Tennessee River into Tennessee, where snow blanketed the ground.

Lows early Friday were predicted in the mid-20s as far south as central Alabama, and temperatures may not rise much above freezing in the northern end of Alabama on Friday.

Heavy machinery loaded a truck with salt to spread on streets in Florence, the TimesDaily reported, and the city convention center opened in Birmingham as a place for people to seek refuge from the cold. The state-run U.S. Space and Rocket Center in Huntsville closed as a precaution.

Alabama was at the southern end of a weather system that forecasters said could spread winter precipitation from eastern Colorado across the Midwest into the Northeast as far as the northern tip of Maine.

Between 2 inches (5 centimeters) and 6 inches (15 centimeters) of snow fell across much of the area late Sunday and early Monday, with a few areas receiving 7 inches (18 centimeters), the weather service said.