DES MOINES (AP) — Officials warned drivers in western Iowa to slow down Thursday after responding to numerous reports of cars sliding off the road because of black ice lingering from a major snowstorm.

The icy road conditions can be attributed to cold weather that’s keeping salt and sand from working against the ice.

The Iowa State Patrol said black ice remains on many roadways, and some of it appears clear to unsuspecting drivers. It’s led to several reports of single-vehicle crashes. Towing has been restricted along Interstate 29 from Missouri Valley to Sioux City, and several more crashes have been reported along Interstate 80.