Around the Deep South, slick roads were causing problems. In North Texas, at least four people died in traffic accidents on icy roads –- including a Dallas firefighter who was killed when a car, sliding on the ice, knocked him off an overpass while he was trying to help a fellow driver, authorities said.
While officials remained worried about the South, the Northeast was expected to get slammed, too. Winter storm warnings expanded to include Philadelphia and New York City this morning, with those warnings lasting from midnight Thursday until 6 a.m. Friday.
The storm was expected to intensify and move up the East Coast today into tonight, with snow forecast to fall in Washington, D.C., and New York City overnight, leading to a slow, cold morning commute for the Northeast.
ABC News' Samantha Wnek and the Associated Press contributed to this report.