Chicago ? Hundreds of airline flights were grounded Wednesday, a major league baseball game was called and six people were killed in accidents on icy roads as yet another spring snowstorm hit the upper Midwest.

North Dakota and South Dakota both measured about 7 inches, and 5 inches fell in Madison, Wis.

“It’s kind of flying sideways,” hardware store owner Harvey Neu said in Menomonee Falls, Wis. “It’s not like a gently falling snowfall. It’s more of a get-out-of-my-face type of thing.”

About 500 flights were canceled at O’Hare International Airport because of poor visibility, said city aviation spokesman Gregg Cunningham.

Milwaukee’s General Mitchell International Airport also had delays and cancellations.

Six people were killed in two separate accidents in Iowa, including a woman and her two children when their minivan collided with another minivan in the state’s south-central region.

Wednesday’s Houston Astros at Chicago Cubs game was postponed because of the storm. During the weekend, heavy snow wiped out scheduled Angels-Indians games for four straight days at Cleveland, and their contest was finally moved to Milwaukee’s enclosed field.