A new report from the National Weather Service concluded that a combination of drier soil, recent agricultural tilling, and dry windy conditions formed the rare dust storm that swept through Central Illinois on May 16.
Sweeping across Illinois, Indiana and parts of Michigan, the event resulted in a rare dust storm warning, drops in visibility, multiple car crashes and closed roadways.
This dust storm was analyzed by National Weather Service Senior Service Hydrologist W. Scott Lincoln, in a report released Thursday. He concluded that a combination of low moisture in the soil of farming fields, agricultural tilling and dry straight-line winds were the leading causes of this rare but not unprecedented occurrence.
"It is beyond the scope of this report to provide an in-depth analysis of the agricultural factors that contribute to these events," Lincoln wrote. "From the currently available information, however, a heightened awareness of potential impactful blowing dust events is advised in the weeks after spring planting [typically in May], especially during dry periods with below average soil moisture conditions. Future work on this topic could include simple modeling of potential blowing dust risk using a combination of soil moisture, crop planting schedules, and wind forecasts."
How the storm unfolded
Lincoln's report lays out the timeline of the affected areas while providing an explanation to the cause of the storm.
Around 4:30 p.m. that Friday, the storm originated south of Bloomington and west of Champaign. A "complex of thunderstorms" triggered straight-line winds in Central Illinois that vacuumed up the dry soil. The moisture levels of Central Illinois fields were reportedly below average for May, resulting in airborne dirt and dust.
According to the analysis, the dust pushed rapidly to the north and northeast passing through Bloomington by 5 p.m. When the storm’s leading edge crossed Interstate 74, multiple crashes resulted in a closure of the roadway.
By 5:45 p.m., the storm expanded approximately 40–50 miles wide from north to south. The dust reduced visibility to near zero for residents of the Chicago metropolitan area around 6 p.m., as the storm extended into northeastern Indiana.
The dust storm dissipated by 9 p.m. when it entered southwestern Michigan, and was almost unable to be traced by satellite by 10 p.m. There were no further reported incidents outside of plane groundings at the O’Hare and Midwest airports.
Newspaper articles from the Chicago Tribune and automated weather observations from northeastern Illinois airports were utilized in Lincoln’s climatological context portion of the analysis.
Blowing dust events are unusual but not unprecedented, Lincoln wrote. In Central Illinois they've previously occurred in May 2023, May 2017, June 1990, and May 1983, resulting in vehicle crashes and sometimes fatalities.
