Overview
- The National Weather Service attributed the residue to blowing dust and wildfire smoke or ash transported from the central and southern Plains.
- Strong southwesterly winds aloft, reported near 70–80 mph around 3,500 feet, carried particulates from Kansas, Oklahoma, and Texas into Illinois.
- Rain embedded the particles and deposited them on surfaces, leaving cars across Chicagoland visibly dirty by Wednesday morning.
- Car washes reported long lines and brisk business as residents sought to remove the film, with customers describing mud-like dust after light rain.
- Experts noted the residue is largely a nuisance but cautioned that inhaling fine particulate matter from wildfire smoke poses health risks, as another storm Thursday could bring a similar round.