A wintry storm marching across the continent hit the northern plains with up to 18 inches of snow Monday, and high wind, poor visibility and icy roads combined to close schools.
Western South Dakota got the heaviest snow, with 18 inches at Spearfish and Galena, both in the Black Hills.
Snow fell over much of the northern plains and the upper Mississippi Valley. Rain extended from eastern Nebraska into the upper Great Lakes region and parts of the Ohio Valley.
The storm had brought up to 20 inches of snow Sunday to many ski resorts in Colorado.
Snow driven by northerly winds blowing at 20 to 50 m.p.h. in South Dakota reduced visibility to near zero and produced wind chill readings as low as 30 degrees below zero.
Visibility was zero to a fourth-mile in parts of the northwest and southwest corners of the state. Roads were snowpacked and slippery throughout the northwest part, with light to heavy drifting in many areas.
Dozens of schools were closed across parts of South Dakota and southeastern North Dakota.
Cass County, N.D., Sheriff Donald Rudnick said it appeared that most people heeded warnings about dangerous travel conditions.
"That's one good thing; we haven't had a lot of stalled cars because it looks like most people weren't out in it," Rudnick said.
In Richland County, N.D., dispatcher Lori Kubitz reported that a number of vehicles were blown off icy roads. "The wind is blowing so hard that the plow trucks can't even spread any sand on the roads," she said.
The strong northerly wind ushered arctic air across the plains and kicked up dust that sharply reduced visibility in parts of Kansas, the National Weather Service said.
However, strong southerly winds ahead of an approaching cold front helped to warm temperatures in the middle Mississippi Valley and the lower Ohio Valley into the 50s and 60s, with some readings above 70 degrees.
Peoria, Ill., hit a record 71; St. Louis, Mo., had a record 72; and Springfield, Ill., had a record 72.