Ice and snow has been reported on highways across North Texas, including in the northern most parts of the region, according to a map of conditions from the Texas Department of Public Safety.

Melting snow: What to expect this weekend: Snow that melts during the day and creates pools of water on roads and sidewalks. When temperatures drop overnight, these puddles of water freeze into black ice. This scenario is especially common after snowstorms where the sun partially melts snow during the day, but the temperature drops again at night.

At least five North Texas counties, including Collin, Dallas, Denton, Kaufman and Tarrant, were under a winter storm warning as of 9 a.m.

Maintain at least three times the normal following distance on snow or ice. Normal following distance is typically three seconds behind the vehicle in front of you, so on snow, follow five to six seconds behind. Watch carefully for snow removal equipment and stay at least 200 feet behind snow plows.

Thursday to Saturday will have another dangerous winter situation in the southern U.S. Here's a timeline on where and when you have to be at a certain location to avoid the danger.