Six people were killed and more than 30 people were injured in crashes when a rare dust storm swept through nearby farms and onto Interstate 55 in a rural section of central Illinois, on Monday morning, leading to “zero visibility” conditions, the Illinois State Police said.

The crashes, which took place just before 11 a.m. on a two-mile stretch of road in Farmersville, Ill., south of Springfield, involved about 20 commercial vehicles and 40 to 60 cars, including two tractor-trailers that caught fire, the police said in a statement.

The people injured were between 2 and 80 years old, and their injuries ranged from minor to life-threatening, the authorities said, noting that it had been difficult to extract people from their vehicles, some of which were engulfed in flames.

“This is a difficult scene, something that is very hard to train for, something that we really haven’t experienced locally,” Kevin Schott, the director of Montgomery County’s emergency management agency, said at a news conference on Monday. The Environmental Protection Agency was called on to manage the spillage from some of the diesel trucks.

The dust storm came on rapidly, creating conditions similar to a snowstorm whiteout, in which visibility is greatly reduced, the authorities said. They advised drivers in the region experiencing any dust to turn on their hazard lights, and noted that winds should subside by around 8 p.m. Monday evening, according to the National Weather Service. A blowing dust warning remained in effect for parts of central Illinois until 7 p.m.

The highway, a key artery in the region, remained shut in both directions between milepost 63 and 80, and drivers were urged to seek alternate routes.

Although dust storms can occur anywhere in the United States, they are most common in the Southwest, according to the National Weather Service. They rarely occur in central Illinois, Ben Deubelbeiss, a meteorologist with the service, said.

But a dry stretch, combined with very strong winds, had created Monday’s conditions, Mr. Deubelbeiss added, noting that the Springfield airport — about 30 miles north of the crash site — had recorded just half of its usual rainfall for the month of April. Wind gusts at the airport were blowing up to 40 miles per hour on Monday, he added.

Leyla Arsan, a Chicago resident, said she had been driving along the Interstate 55 on Monday when she began to see dust and smoke. Despite the high winds, Ms. Arsan said, cars did not appear to be slowing down, and “trucks were fishtailing left and right.” She was ultimately forced to turn around on the highway to avoid the crash site about three miles ahead.

Similar conditions caused an eight-vehicle pileup in Amarillo, Texas, last month, but the authorities there said that no one had been seriously injured.

Nick Gorman, who works in Farmersville, said that he had seen a “huge cloud of dust” late Monday morning that tasted like chalk, made him cough and obscured the view for miles. He said he had never experienced a dust storm warning in the village, which has a population of less than 700 people.

“August is whenever it’s really dusty,” Mr. Gorman, 22, said. “It was kind of odd for this time of year.”