Man-made snow plumes: Although no weather systems were in the area to crank out snow, flurries were still falling across parts of Chicago

Chicago Tribune

If you happened to glance at the Chicago radar Tuesday morning, you probably saw something a bit wacky. Although no widespread weather systems were in the area to crank out snow, flurries were still falling across parts of the area. These unusual phenomena were thanks to a supercooled atmosphere interacting with exhaust from a power plant and also the air flow around commercial aircraft.