Weather forecasters expect significant snowfall from an incoming storm system.
A Winter Storm Warning is in effect for far western South Dakota from tonight through tomorrow.
The rest of South Dakota is under a Blizzard Warning from tomorrow through Saturday.
Jeff Chapman with the National Weather Service in Sioux Falls says winds from 40 to 50 miles per hour will combine with several inches of snow, leading to life-threatening travel conditions.
"Across Southeast South Dakota we're going to see some wide-ranging accumulations, but generally very heavy and potentially historic snowfalls...exceeding daily records across much of the area. We're looking for amounts anywhere from possibly as low as 6-8 inches in the far southeast corner of the state, as you get down to Sioux City [Iowa]. With some amounts of 10, maybe 16 inches for portions of south central South Dakota towards east central South Dakota, around the Brookings [and] Flandreau area," Chapman says.
Chapman says strong thunderstorms are possible overnight tonight in Southeast South Dakota. He says windy conditions and hail are possible. Chapman says storms are in the forecast again for tomorrow evening before rain switches to snow.
South Dakota Secretary of Transportation Darin Bergquist says in a statement that the winter storm will "hamper and possibly cripple travel for most of the state." He says "there's a high probability" of interstate closures as the storm impacts South Dakota.