People fired up snowblowers and dug out their shovels Saturday after the first significant snowstorm of the season dumped between a few inches and 20 inches of snow across the Upper Midwest, blanketing a swath from South Dakota to Michigan.

The storm created hazardous travel conditions and caused more than 500 flight cancellations. A blast of much colder air was following the storm.

The National Weather Service said the snow, which first fell in South Dakota, Minnesota, and Iowa on Friday, would head into Canada late Saturday after moving through Illinois, Indiana, and Michigan.

In the southern Wisconsin town of Janesville, between 10 and 20 inches of snow had fallen by late Saturday afternoon.

Southside True Value Hardware manager Matt Krienke said business had been good in the days leading up to the storm, but that it had become "very, very, very, very slick." He added: "People who don't need to drive don't need to be out."

Snow totals in the northern suburbs of Chicago topped initial forecasts of 6 to 10 inches, said National Weather Service meteorologist Amy Seeley - 12.5 inches in Woodstock and 11.7 inches in Roscoe. It's unusual for the area's first snowfall of the season to dump more than 6 inches, she said.

About 60 miles northwest of Chicago, the village of Capron had received 14.6 inches by Saturday morning, spurring village employee Robert Lukes into action clearing sidewalks with his snowblower in the community of about 1,400. He said the snow was wet, with a layer of slush underneath that made the work slow going.