OMAHA, Neb. (AP) – A midwinter storm has deposited more than 18 inches of snow on northern Nebraska and up to a foot on northern Iowa. The Nebraska and Iowa highway departments said Wednesday that highways are covered with snow and that motorists should be wary of slick spots. Many school districts in both states have canceled classes or are opening late.

Authorities say a woman died Tuesday after she lost control of her vehicle and collided with another on a slickened highway near Le Mars in northwest Iowa. The National Weather Service says 18 inches of snow was reported Tuesday evening at Bayard in the Nebraska Panhandle. Eleven inches of snow was reported in Iowa’s Sioux County.

The service says the slow-moving, eastbound system has prompted storm warnings in Minnesota and Wisconsin.