MILWAUKEE (AP) — A major storm piled snow more than a foot deep across parts of the Plains and Midwest on Wednesday, closing schools and businesses, grounding more than 1,000 airline flights and making highways hazardous.

A foot of snow had fallen in parts of Wisconsin, Iowa and Kansas. The National Weather Service said up to 18 inches was expected in southern Wisconsin.

Less snow fell in Missouri, with 6 inches in places, but it was enough to form ice on bridges and highway ramps. A 12-car pileup near Springfield closed Interstate 44 for about an hour.

“When those things freeze, they all go at the same time,” said Earl Wallace, a spokesman for Missouri’s highway department.

One Wisconsin traffic death was blamed on slippery pavement, and hundreds of businesses and schools were closed across the southern part of the state.

Nicole Rodriguez gave herself plenty of time to get from her suburban home to her job in downtown Milwaukee.

“It wasn’t bad. I left an hour and a half early, and arrived in plenty of time,” said Rodriguez, 35, but she said she did see some slipping and sliding on roadways.

The foot of snow that fell at Oskaloosa, Iowa, came on top of 12 inches that fell Sunday, making it nearly impossible for people to get around.

“It’s a mess. Nobody is out too much and if they are they’re getting stuck,” said Wade Schneckler, 47, of Oskaloosa.

Wind piled the snow into drifts up to 4 feet high near Monore, Iowa, and drifts were 2 to 3 feet high in western Kansas.

Schools and universities canceled classes in parts of Kansas. In Iowa, Des Moines school officials told nearly 31,000 students to stay home after 8 inches of snow fell in Polk County. Dozens of northern Illinois schools closed for the day because of the snow and others planned to close early.

Nine inches of snow was forecast for Chicago, where airlines canceled about 1,000 flights at O’Hare International Airport by midday and about 50 flights at Midway Airport, said Karen Pride, spokeswoman for the city’s aviation department. Remaining flights had 45-minute delays, she said.

Police in the snow-covered states reported numerous traffic accidents on slippery roads.

Iowa transportation officials closed some major highways for various times because of accidents, and said blizzard conditions made travel unsafe in eastern Iowa.

Even before this storm, Iowa’s statewide average snowfall this winter was 23.5 inches, nearly double last winter’s 12.7 inches, with spring still more than a month away, the weather service said.

All that snow had led to shortages of road salt in many communities in Iowa and Illinois, including Tipton, Iowa, which has only 25 tons remaining of its 150-ton supply. Getting more will be difficult because ice on the Mississippi River has blocked barge traffic.

“You just got to roll with the punches,” said Tipton Public Works Director Steve Nash. “We’ve got enough to last us for two or three weeks, but if this snow thing continues through March, then we could be in trouble.”

This also is a snowy winter in parts of the West, where the resort town of Coeur d’Alene, Idaho, had a seasonal record of 127 inches as of Tuesday night, beating the old mark of 124.2 inches set in the winter of 1915-16. The weather service forecast a half-foot more by nightfall Thursday.