SIOUX FALLS, S.D. (KELO) -- Portions of South Dakota and southwestern Minnesota were still under a dense fog advisory until 12 noon Tuesday. Photos from South Dakota Department of Transportation cameras show fog was lifting in some areas west of Sioux Falls at around 11 a.m. Tuesday. Fog could still be seen in other areas. I-90 Mitchell Highway 34 HowardI-29 at 41st Sioux FallsI-29 Dell RapidsI-29 WardU.S. 81 Arlington The South Dakota Highway Patrol advised drivers to turn on headlights, watch their speed, stay alert to changing conditions, increase following distance and that all should wear seatbelts. d turn the headlights on. Follow the weather with the KELOLAND weather app. Check road conditions in South Dakota with SD 511.