DES MOINES, Iowa – The first widespread snowstorm of the season plodded across the Midwest on Thursday, as whiteout conditions sent drivers sliding over slick roads and some travelers were forced to scramble for alternate ways to get to their holiday destinations.

The storm, which dumped a foot of snow in parts of Iowa and more than 19 inches in Wisconsin’s capital, was part of a system that began in the Rockies earlier in the week before trekking into the Midwest. It was expected to move across the Great Lakes overnight before moving into Canada.

The storm led airlines to cancel about 1,000 flights ahead of the Christmas holiday — relatively few compared to past big storms, though the number was climbing.

Most of the canceled flights were at Chicago’s two international airports. The storm made travel difficult from Kansas to Wisconsin, forcing road closures, including a 120-mile stretch of Interstate 35 from Ames, Iowa through Albert Lea, Minn. Iowa and Wisconsin activated National Guard troops to help rescue stranded drivers.

In Iowa, two people were killed and seven injured in a 25-vehicle pileup.