ST. LOUIS — Hundreds of snow plows and salt spreaders took to the highways of the nation’s heartland today, preparing for a winter storm that could dump up to a foot of snow in some regions and bring dangerous freezing rain and sleet to others.

Winter storm warnings were issued from Colorado through Illinois. By midday today, heavy snow was already falling in Colorado and western Kansas.

National Weather Service meteorologist Jayson Gosselin said parts of Colorado, Kansas and northern Missouri could get 10 to 12 inches of snow. Further south, freezing rain and sleet could make driving treacherous.

Officials feared the winter storm would be the worst in the Midwest since the Groundhog Day blizzard in 2011. A two-day storm that began Feb. 1, 2011, was blamed in about two dozen deaths and left hundreds of thousands without power, some for several days. At its peak, the storm created white-out conditions so intense that Interstate 70 was shut down across the entire state of Missouri.

“We’re not going to see that type of storm, but it’s certainly the most impactful in the last two winters,” said Gosselin, who works in suburban St. Louis.

Tim Chojnacki, spokesman for the Missouri Department of Transportation, said graders, snow blowers and salt-spreading trucks were at the ready. The salt trucks planned to be out before the wintry mix arrived in the Show-Me State in hopes that the precipitation would largely melt upon impact.

Gosselin said areas like St. Louis, southern Missouri and parts of Texas, Oklahoma and Arkansas may get little to no snow, but the sleet and freezing rain could present more of a challenge. Ice accumulations could reach a half-inch in some places.

“Sleet is no fun to drive on,” Gosselin said. “Especially if you get a couple of inches, which could happen. It doesn’t melt, and it’s very heavy to move. It’s difficult to shovel, you can’t really plow it and the chemicals don’t work as well.”

Colorado Department of Transportation spokeswoman Mindy Crane said hundreds of plows were being deployed for what is expected to be one of the most significant snow storms of the season. Several schools called off classes today as snow began to accumulate.

Just the threat of snow is having a big impact in Nebraska. The state legislature postponed Thursday committee hearings and University of Nebraska officials moved a Big 10 men’s basketball game against Iowa from Thursday to Saturday.

Also in Lincoln, Nebraska’s capital city put out a call for more “snow angels” — a program that puts volunteers in touch with those unable to remove snow from their sidewalks and driveways. Lincoln is expecting 8 inches of snow by Thursday and city ordinances require people to clear their sidewalks.

Gosselin said precipitation is generally expected to drop off as the storm makes its way east. Chicago and parts of Indiana, he said, could get about 2 inches of snow and some sleet.

— Associated Press