An early spring snowstorm forced the cancellation of more than 100 flights at Denver International Airport and closed several roads Saturday as it moved eastward, dumping more than a foot of snow in some places.

The snow started falling around midnight in northeast Colorado and then moved into northwest Kansas and southwest Nebraska.

Up to 18 inches was expected in northwest Kansas and northeast Colorado, said Jerry Killingsworth, a meteorologist for the National Weather Service, and I-70 was shut down Saturday from Denver to Colby, Kan., because of poor visibility. The northbound lanes of I-25 also were closed south of Fort Collins, Colo., because of multiple accidents.

“It’s a mess here,” said Killingsworth, who is based in Goodland, Kan. “Heavy, wet snow, tree limbs down.”

As the system moved eastward, it threatened to inconvenience fans attending the NCAA men’s college basketball tournament in Kansas City. Pamela Murray, a meteorologist in Pleasant Hill, Mo., saidt he heaviest snowfall was expected overnight.

But Dan Gavitt, vice president of the NCAA men’s basketball championships, said the tournament was prepared.

“This region routinely has winter snow and has the appropriate equipment and procedures to manage these winter conditions,” Gavitt said in written statement. “We encourage fans planning to attend games to pay attention to the weather, use good judgment and follow any directions from local authorities regarding travel and weather.”

North Carolina coach Roy Williams was nonplussed.

“It’s no distraction, unless the roof goes off, we’ll still be able to play and the whole bit like that,” Williams said.

At Denver International Airport, spokesman Heath Montgomery said about 106 flights had been canceled. In the mountains, the Colorado Avalanche Information Center said the new snow could create avalanche hazards.

The system was forecast to move into Illinois and Indiana overnight, and western Ohio today.

Meteorologist Dan Smith with the National Weather Service in Lincoln, Ill., said snowstorms aren’t uncommon in early spring. The latest the area has seen snow, he said, was April 23 in 1910.

“One good thing about them is it doesn’t matter how much you get, it usually doesn’t stick around too long because temperatures start to warm up pretty good,” he said.

Farther south, tornadoes were possible in Louisiana and Mississippi, while strong winds and low humidity could lead to forest fires and wildfires in parts of New Mexico and west Texas.