Blizzard Grounds Flights in Chicago With Warning for Millions in Northern U.S.

Planes were grounded for more than two hours at Chicago’s largest airport on Friday morning as a blizzard dumped snow and ice across much of the northern United States, disrupting commutes, air travel and the school day for millions of Americans.

The blizzard also caused headaches for Republican presidential candidates in Iowa ahead of Monday’s caucus, with at least one campaign forced to cancel events, citing what forecasters for the National Weather Service called “life-threatening winter weather.”

Nearly 30 million Americans, mostly in the Midwest and around the Great Lakes, were under a winter storm warning early Friday, according to the Weather Service, which said that more than a foot of snow could fall in parts of the region.

The storm was expected to be followed by a major Arctic air mass that will stretch across the country over the three-day weekend. Temperatures across much of the United States will be the coldest of the winter so far.

In Des Moines, about three inches of light, fluffy snow fell overnight. The snow began to slack off after the sun came up, but more is expected, and winds are forecast to pick up later Friday morning.

Schools throughout Iowa were closed for the day. Parts of Interstate 80 between Des Moines and Iowa City were repeatedly snagged overnight by jackknifed tractor-trailers and multiple-car pileups, the Department of Transportation reported.

Officials warned that bands of heavy snow and high winds were making it difficult for drivers to see across Iowa. They posted a map on social media showing that almost all of the major routes in the southern part of the state were completely covered by snow.

In Lincoln, Neb., the airport was still open early Friday, but all outgoing flights had been canceled because of the howling wind and snow. Major highways were open, but most roads were covered after a full night of heavy snowfall.

Schools in the Lincoln area canceled classes, marking the third snow day this week for students in the Lincoln Public School system.

Nebraska lawmakers, meeting for the first week of their legislative session, decided to put off major business for the day. Speaker John Arch told local reporters he was concerned that it would be unsafe for lawmakers to travel to the statehouse Friday morning.

Chris Cameron contributed reporting from Washington, D.C.