Two power plants in Norfolk, Neb. caused two inches of snowfall throughout parts of Nebraska, including some flakes that were up to an inch wide.
The National Weather Service Omaha tweeted on Tuesday that steam exhaust from industrial plants east of Norfolk caused snow the Omaha Metro area, with snow falling over towns as far as 100 miles away.
NWS Meteorologist Brian Barjenbruch tells TIME that snowfall caused by steam from power plants are fairly rare but it does happen from time to time. Barjenbruch said over the last year he saw similar situations in Northwest Indiana and Dodge City, Kan.
A power plant can cause snow, Barjenbruch says, when steam that usually goes up into the air and evaporates actually interacts with ice in the air. In the case of Norfolk, Barjenbruch says, there were perfect conditions that allowed for the snow to form.
‘There are a few industrial plants on the Eastside of Nebraska and they’re working as they would on any other day in the past two days but with a lot of moisture and the perfect range of temperature to produce snowfall.” he says. Barjenbruch says the optimal temperature to produce snow is -12 to -18 degrees celsius. He adds that snow formed under those conditions can produce bigger flakes like the ones that were seen in Norfolk.
Barjenbruch says that as a meteorologist, it is a fun phenomenon to witness.
“Its not something we see too often, so in a way it’s one of those things thats makes our job interesting.” he said.