CHICAGO — Frigid, subzero temperatures were expected to roll in Sunday afternoon, evening and into Monday across a wide swath of the United States. Some residents in Midwestern states were digging out from nearly a foot of snow Sunday afternoon, and grocery stores were selling out of essentials.

Hazardous travel conditions led to canceled flights and prompted warnings from transportation officials that only those who absolutely need to venture out should do so. Some schools canceled Monday classes, and local governments and charities worked to be sure shelters were available for anyone who needed them.


Drivers in northern Delaware have been dealing with treacherous conditions resulting from freezing rain. The state Department of Transportation warned of black ice and other dangerous conditions, especially on bridges and overpasses.


Illinois residents were digging out of more snow Sunday afternoon — as much as 10 inches in some parts of the state. Aviation officials say about 1,200 flights were canceled at Chicago’s O’Hare International Airport on Sunday morning, with about 60 cancelled at Midway International Airport.


A winter storm had already dropped 5 inches on parts of Indiana and some areas could see up to a foot as the state prepares for dangerous Arctic air expected to bring subzero wind chills. Gov. Mike Pence ordered nearly 100 Indiana National Guard members to be ready to help rescue stranded motorists, move people to shelters and assist local emergency services workers in reaching people who need medical help. The state General Assembly postponed Monday’s opening of its 2014 session.


Some Iowa schools have canceled classes to keep children out of the subzero temperatures expected in the coming days. The National Weather Service says temperatures will fall as low as 15-25 degrees below zero Sunday night and Monday with wind chills of 35-60 degrees below zero.


Even though the initial forecast for snow has been scaled back, flights for Monday and Tuesday were canceled at Barkley Regional Airport in Paducah. Organizations including churches and the Salvation Army were planning to open warming centers in some cities.


Conditions in some parts of Michigan were relatively balmy Sunday morning, with temperatures as high as 32 degrees in the far southeast. But the harshest winter conditions in 20 years are heading for the Lower Peninsula, with up to 15 inches of snow forecast for parts of the state by late Sunday followed by temperatures diving as low as minus 15.


The cold snap that the National Weather Service is calling “historic and dangerous” has arrived in Minnesota. Temperatures were down to 8 degrees below zero in the Twin Cities area around midmorning Sunday, and temperatures are expected to dip between 25 below and 40 below overnight, with wind chills plummeting to between 55 below and 65 below.


Heavy snow combined with strong winds and cold created dangerous conditions Sunday over much of Missouri, prompting warnings that only those who absolutely need to venture out should do so. The state Department of Transportation said it was so cold the salt used to melt ice and snow wasn’t very effective and that conditions were so bad they were a danger even to employees driving the plows and trucks.


Officials are warning that frostbite and hypothermia are possible if Nebraskans aren’t prepared for the cold moving into the state on Sunday afternoon. And the Nebraska Humane Society urged pet owners to bring their animals inside.


A plane slid into snow as it turned onto a taxiway after landing at John F. Kennedy International Airport on Sunday, disrupting flights at the airport for two hours. No injuries were immediately reported, according to a Federal Aviation Administration spokeswoman.


The North Dakota Department of Transportation has issued a travel alert for the southwestern part of the state as blowing snow is reducing visibility. Drivers were encouraged to reduce speeds and be ready for rapidly changing conditions and extremely cold wind chills.


Winter weather caused the cancellation of flights and delays of more than three hours at airports in Nashville and Memphis on Sunday. The Metro Nashville government said it was partnering with local organizations to make sure shelters were available.


The National Weather Service has issued wind chill warnings that take effect Monday evening from the Alleghany Highlands southeast to the Virginia Piedmont, including the Roanoke and New River valleys, and areas west of the Blue Ridge. Those areas could see wind chills of minus 30 degrees.


The National Weather Service says dangerously cold air is expected to settle over Wisconsin on Sunday afternoon and become life-threatening Sunday night through Tuesday. Sunday’s NFL playoff game in Green Bay’s Lambeau Field could be among one of the coldest ever played: A frigid minus 2 degrees when the Packers and San Francisco 49ers kick off around 3:30 p.m.