As of 9:30 p.m., a total of 72 vehicles, including commercial vehicles cars, were involved in the crashes just before 11 a.m. They started on the northbound side, and some eventually took place on the southbound side, as well, along a 2-mile stretch, Illinois State Police said.
So far, all six deaths took place in the northbound lanes, police said. So far state police have released the identity of one victim, 88-year-old Shirley Harper of Franklin, Wis.
"It felt like a war zone," said Quenna Penson, who was driving home to Chicago from downstate. "We could see bodies that were just lifeless laying in the grass on the side of the road."
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Illinois State Police said troopers responded to I-55 near mile post 76 in Montgomery County for multiple crashes with injuries, due to excessive winds blowing dirt from farm fields across the highway.
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The injuries range from minor to life-threatening, and those hurt are 2 to 80 years old.
Two semitrailers caught fire. There were also reports of an explosion.
"We started to hear the booms from the gasoline tanks, and it was one right after the other," Penson said.
The highway is shut down in both directions from mile post 63 to 80, ISP said.
Visibility was low due to blowing freshly plowed field soil.
"The proper procedure would be to put your hazards on, get on the side of the road and let the dust cloud go, but people kept just driving into it," said driver Nathan Cormier. "If I hadn't moved to the left lane, I would have been crushed behind the two red cars behind me."
The Illinois Department of Transportation tweeted just after 11:15 a.m. that I-55 was closed in both directions between Divernon and Farmersville, Illinois in Sangamon and Montgomery counties.
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Burned up truck beds, disjointed tractor trailers and mangled vehicles of every kind were strewn across the highway after the incident.
U.S. Rep. Nikki Budzinski, D-Springfield, tweeted, "My team and I are closely following the devastating crash on I-55 as authorities learn more. Please be safe as this situation continues to unfold."
Traffic is being detoured on IL-48 and IL-104 through Taylorville, IDOT said. Motorists are asked to avoid the area.
The roadway is not expected to reopen until at least Tuesday morning.
Police believe everyone has been transported from the scene, but hundreds of officials were conducting a second search of vehicles Monday afternoon.
State climatologist Trent Ford on Illinois dust storm
Several helicopters responded to the scene.
Drivers were in disbelief and said visibility was almost non-existent once you got inside the cloud, which moved over I-55 without warning.
Many didn't have time to brake, slamming into cars and trucks in their path.
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Cormier captured video of the scene. He was able to slow down just in time to avoid being hit by two cars around him, and one of the first cars to see what loomed ahead over the southbound lanes.
Cormier said he hopped out of his car and started helping pull other stunned drivers from their cars before emergency responders could even cut through the traffic snarl to start evacuating drivers.
He was covered in dust after the effort.
"I know the one car in front of me. He rear-ended a truck, and he had cracked ribs, a lot of facial contusions from airbag deployments. It was a doozy day. It's still going. When I drove into it, it was light at first, and then it just became a, pretty much a gray out," he said.
Cormier was stranded for about four hours.
By later in the day Monday, he was able to get out of the mess, as crews slowly work to clear debris.
Dust storms like this are not uncommon in Illinois.
Dust storms not uncommon in Illinois
ABC7 Chicago meteorologist Larry Mowry said winds have been 35 to 45 mph in the area, which has been dry.
Farmers also had just been planting, said Megan Styles, environmental scientist University of Illinois Springfield.
The storm seems to cover 20 to 30 miles, originating several miles west of the I-55 corridor.
The stretch of I-55 involved is about 25 miles south of Springfield.