Folks near Colfax, Wisconsin got a bunch of unexpected snow on December 4, and nobody else around the region just northwest of Eau Claire got any at all due to a bizarre weather phenomenon that the National Weather Service just recently offered an explanation for.

A very small area near Colfax that was about 15 miles long and 2-3 miles wide got upwards of 6 inches of snow over a 9-hour period, while the rest of the area saw no snow. In the radar graphic the Twin Cities NWS office tweeted out late last week, you can see the some evidence of the small snow plume pop up on radar very strangely.

After looking into the situation, the NWS determined the "snow plume" was created/enhanced by steam from factories upwind from where the plume developed.

National Weather Service Meteorologist Caleb Grunzke told WQOW TV that several factors played a role in this "man-made snow", including steam from the factories in question, which released warm moist air into the surrounding cold air. Similarly to how lake effect snow happens, as the warm, moist air cools, it can't hold the same amount of moisture anymore, leading to snow falling. The right mix of factors need to be present for it to happen, which is what makes it so rare for this particular area to have seen this type of snow event.