The snow tapered off by this morning in Des Moines, but strong winds are creating whiteout conditions. A 25-vehicle pileup on Interstate 80 north of Des Moines killed one person. Police say drivers were blinded by blowing snow and didn't see vehicles that had stopped or slowed.
Some unplowed streets in the city are nearly impossible to navigate in anything other than a four-wheel-drive vehicle.
The windy conditions have contributed to tens of thousands of power outages.
Forecasters say the snow cover will drag temperatures much lower in Nebraska and Iowa, with readings in the single digits.
People who are trying to fly today in advance of the Christmas holiday are finding their plans disrupted. Officials at O'Hare International Airport in Chicago report some flight delays and dozens of cancellations.
Chicago began the day with heavy fog and cold, driving rain -- and a forecast for snow later in the day.