It doesn’t happen often, but the flurries out over Lake Michigan this afternoon are “industry effect” snow flurries (also called “industrial effect” or “factory effect” snow) The industry near Gary and Burns Harbor has helped to form two distinct areas of flurries out over the lake with our light southwest breeze helping to direct the flurries out over open water.
The steam and particulates released from the smokestack plumes help to aide in snow crystal formation.
The steam rises and forms snow crystals which are then directed out over the lake due to our breeze. The first area of snow is from the industry near Gary:
The second from industry near Burns Harbor:
The optimal temperature to produce snow is -12 to -20 degrees Celsius. Snow that is formed under those conditions can produce bigger flakes than those currently offshore.
The snow flurries will likely linger through the evening as atmospheric conditions remain supportive of snow crystal development, but activity should remain offshore.
Here’s what it looked like on radar: