A Factory-Effect Snowstorm? Yeah, It Really Happened.

Radar imagery from Thanksgiving shows a 100-mile
long band of snow along Interstate 94 in Wisconsin
caused by, of all things,  factory.

Lake effect snowstorms are in the news this weekend. 

But here's an odd one: 

A factory-effect snowstorm shut down part of an Interstate highway in Wisconsin. That's right, a factory caused a snowstorm.

As the Washington Post describes it, a glass factory near Menomonie Wisconsin spewed steam and a few particles into the air on Thanksgiving, like it pretty much always does.

It was a dull Wisconsin morning, cold, damp, with a low overcast. Temperatures were in the 20s, and it was much colder than that a few thousand feet up.

The low stratus deck consisted of zillions of supercooled water droplets. 

Supercooled water droplets are at a temperature below freezing, but are still liquid. Those supercooled droplets will freeze if something hits them, like particles in the air or ice crystals.

The steam belching from the glass factory did the trick. As soon as the emissions hit that supercooled low overcast, the droplets froze and changed into snowflakes. Which fell out of the sky. In droves.

It was obviously only a very narrow band, as just one set of factory smokestacks can do so much. But the snow band pretty much paralleled Interstate 94 win Wisconsin for up to 100 miles. 

Hard to see due to thick snow falling, but traffic tie
ups on Interstate 94 in Wisconsin Thursday caused
by a weird factory-effect snowstorm. 

The variable visibility and slick pavement created by the snow caused some crashes which temporarily closed part of the Interstate.  There were reports of 16 crashes within five hours, including a six-car pileup. 

Snowfall amounts were fairly modest, as again, a factory isn't a lake and doesn't have the power to produce feet of snow like Lakes Erie and Ontario can in western New York. 

Still a good three inches of snow fell along some of the path of this factory-effect snow, so that's pretty impressive. 

This isn't the first time something like this happened but it's one of the more impressive. Emissions from power plants and even steam from relatively small rivers can create snow. Sometimes, it doesn't take much to make it snow.