'Localized' Illinois dust storms fueled by rare chain of weather events

Monday's dust storm, which led to scores of car crashes and seven deaths on I-55 south of Springfield, was caused by a chain of extremely localized weather conditions that have been recorded only once in the Chicago area, weather experts said.

Though unusual for the state, Illinois dust storms, when they occur, are most common in May and June in rural areas as farming activities ramp up. Loose soil from freshly plowed farm fields, combined with dry conditions and high winds, can create plumes of dust and near-zero visibility, the situation drivers found themselves in on Monday.

The storms are more common in the Plains and Southwestern U.S., but dry conditions fueled by a lack of recent substantial precipitation can lead to events like Monday's storm, where visibility on the road can change in an instant.

Jeffrey Frame, a professor of atmospheric sciences at the University of Illinois Champaign-Urbana, said Monday's storm was extremely localized, and it took several factors to line up to create those weather conditions.

“Visibility can change very, very rapidly, in a short time, depending on what the field is upwind of you,” Frame said. “You're not going to have nearly as much dust coming off of grass as you will off of a recently tilled, recently planted, dry field that hasn't seen rain in several days.”

Frame compared the visibility conditions to a type of event more common for Illinois: snow squalls, which create a sudden whiteout rather than a dust storm's brownout.

Frame added that there is no concern that these types of events could increase in frequency in the future.

“In terms of climate change, there have been no stories about this. I think it was a very, very localized incident,” he said.

Notable past dust storms in central Illinois include an event in May 2017 in which two people were killed in accidents caused by blowing dust. The storm required the closure of I-72 from Jacksonville to Springfield, and I-55 from McLean to Bloomington.

Another storm in June 1990 led to an accident that injured five people and closed I-57 from Arcola to Mattoon due to blowing dust.

One comparable dust storm that took place in the Chicago region occurred May 24, 2012, when near-zero visibility was reported on I-88 near Maple Park. The event, also close to agricultural fields, led to an accident with three injuries near Watson Road.

National Weather Service meteorologist Kirk Huettl, based in central Illinois, said that though the forecast service can track dust plumes using satellites, the storms are difficult to predict, because the technology does not indicate visibility. Rather, the service depends on surface observations from spotters on the ground.

“Some of our counties may only have one observation site per county, so it's not a real network of visibility,” Huettl said. “It'd be great if we had visibility every mile or two to detect it better.”

The central Illinois weather forecast office put out a dust storm warning — exceedingly rare in Illinois — on Monday and Tuesday.

The office recommends drivers avoid the storms if possible, and if caught in one, “pull off the road, turn off your lights and keep your foot off the brake,” according to the storm warning.

Huettl added that farmers are not required to stop plowing during a dust storm warning, though the office encourages them to stop if they can.

The office issued a dust storm warning Monday at 1:46 p.m. following the crashes, which occurred shortly before 11 a.m.

“I doubt that (the weather service) is able to warn for that in advance or predict something like this on a fairly ordinary day,” Frame added. “It was cold, it was blustery, but it's not like it snowed or anything. It's not like people's roofs were getting blown off or anything like that. It's just one of those things that's surprising to see, and tragic to see.”

• Jenny Whidden is a climate change and environment writer working with the Herald through a partnership with Report For America supported by The Nature Conservancy. To help support her work with a tax-deductible donation, see dailyherald.com/rfa.