At least six people were killed and over 30 more were injured after an unprecedented dust storm along a major highway in central Illinois on Monday caused dozens of vehicle crashes, state police said.

Iran PressAmerica: The late morning crashes involved up to 90 cars and multiple tractor-trailers, two of which caught fire, Illinois State Police Maj. Ryan Starrick said.

He said at least six people died, all in the northbound lanes, and more than 30 people on both sides of I-55 were transported to hospitals with injuries.

Illinois State Police said in the statement that the “excessive winds blowing dirt” during the storm caused zero visibility for the drivers, resulting in the pileup. The police said that at 10:55 a.m., one crash occurred on the northbound Interstate 55 and multiple crashes occurred in a two-mile stretch of the southbound lane.

I-55 was shut down in both directions in Montgomery County, 75 miles (120 kilometers) north of St. Louis, and likely won’t reopen until Tuesday.

Winds at the time were gusting between 35 mph (56 kph) and 45 mph (74 kph), the National Weather Service said.

Kevin Schott, director of emergency services in Montgomery County, said it was a “very difficult scene” and one that’s “very hard to train for.”