Heavy snow and ice were expected across a wide swath of the country. At least three governors had declared states of emergency.
More than a dozen states were under some type of winter weather warning on Wednesday, as an enormous storm began its push across a large swath of the United States, with moderate snow falling from New Mexico to Illinois.
Airlines canceled more than 1,200 flights on Wednesday, with most of the cancellations focused on the Midwest, according to the flight-tracking service FlightAware.
In its latest forecast, the National Weather Service said the “significant” system would bring a mixed bag of wintry precipitation, including heavy snow, sleet and freezing rain, to the Central United States through Thursday morning before pushing toward the Northeast.
Heavy snow was forecast for the Southern Rockies and from the Central and Southern Plains and Middle Mississippi Valley through the Great Lakes, the Weather Service said. A “corridor of heavy ice” was also expected from Texas through the Ohio River Valley.
The snow began Tuesday afternoon in New Mexico, the Weather Service said, warning that snow would develop in the lower elevations on Wednesday. The heaviest of it was expected to arrive in the evening, with temperatures well below freezing. Parts of New Mexico were expected to get as much as 14 inches of snow. Colorado and Kansas could see similar conditions and morning commutes in those states were expected to be difficult.
Around the Chicago area, nearly two inches of snow had fallen by early Wednesday, the Weather Service said. The snow was expected to fall at a rate of up to 1.5 inches per hour through noon. “Consider postponing travel,” meteorologists said. “Bring an emergency kit if you must drive.”
In Illinois, Gov. J.B. Pritzker said he had activated about 130 National Guard members to help respond to the storm, which he said could bring as much as 20 inches of snow to the central part of the state and create blizzard and white out conditions on some roadways. “At home, make sure that your household has the essentials: food, water, medicine,” Mr. Pritzker said. “Do not travel or drive if you can avoid doing so.”
Gov. Mike Parson of Missouri declared a state of emergency and noted that more than half of the state was already under a winter storm warning, with parts of central Missouri possibly getting eight to 15 inches of snow. “Severe winter weather isn’t something we are strangers to,” he said in a statement. “But we must be prepared for the worst.”
In addition to declaring a state of emergency, Gov. Kevin Stitt of Oklahoma said more than 500 trucks statewide were ready with 123,000 tons of salt and sand. A winter storm warning will be in effect for eastern parts of Oklahoma as well as west-central Arkansas, from noon on Wednesday through midnight Thursday, according to the Weather Service. Gusty winds and ice accumulations could lead to power outages throughout the area, the warning said.
“Power outages of 24 hours and possibly up to several days should be anticipated across portions of far southeast Oklahoma,” the Weather Service said in a warning.
Other parts of the United States unaccustomed to such wintry weather, like central Texas, were bracing for snow and freezing wind chills.
Some freezing rain and ice accumulation were expected by Wednesday evening in parts of Dallas, Fort Worth and surrounding areas. “We are most concerned about the icing potential which is the worst to drive on and can cause power outages and tree breakage,” said the Weather Service in Fort Worth.
Ahead of the storm, the Dallas Independent School District, one of the largest districts in North Texas, announced its schools would be closed on Thursday and Friday.
Two or three waves of snowfall were expected to ultimately bring four to five inches of snow in south-central and eastern Kansas, and as much as a foot of snow in far eastern Kansas, according to Kevin Darmofal, a meteorologist in the state with the Weather Service. Winds up to 30 miles per hour on Wednesday night could complicate snow removal efforts in Kansas, Mr. Darmofal said. Those winds “will cause blowing and drifting snow,” which would also make traveling more difficult, he said.
In Michigan, nine to 16 inches of snow was expected, through late Thursday night, the Weather Service announced.
This week’s winter storm is the latest to hit the United States this year. A snowstorm last weekend along the East Coast dumped nearly two feet of snow in Boston, tying a single-day record set in 2003.
Jesus Jiménez contributed reporting.
