Nebraskans are being dusted in snow generated by the steam from power plants right now.

The National Weather Service reported on Monday that two plants in Norfolk are responsible for snow in Seward and Lincoln, located downwind of the power facilities.

The phenomenon of industrial snow is “not super common in this area,” Brian Barjenbruch, a meteorologist with the National Weather Service in Valley, Nebraska told Motherboard.

“What’s causing the snow to develop today is the addition of moisture,” Barjenbruch explained. “The atmosphere is currently at the perfect temperature for snow product,” and as the steam escapes—instead of evaporating—it adds moisture and warmth to the ice crystal-laden clouds, giving them a boost at producing snow.

It’s similar to lake-effect snow, which occurs when cold air moves across relatively warmer water, accumulating moisture which then falls as snow, usually over land.

Earlier this year, a power plant near the Kentucky-Indiana border created light flurries. And the Beaver Valley Nuclear Power Plant in Pennsylvania caused a “freak storm” in 2013.

The National Weather Service said it didn’t know which plants were responsible for the flakes.

“Meteorologically speaking, it looks like the winds are going to decrease and temperatures are going to cool off this evening, putting an end it,” Barjenbruch predicted. Up to two inches have fallen in some areas.

As for the snow itself, Barjenbruch said it’s nothing special.