A pair of industrial plants in Norfolk were credited with a band of snow that stretched as far south as Seward on Monday.
The National Weather Service determined that steam from the plants was adding moisture and warmth to the clouds, creating snow, including reports of snowflakes as large as 1 inch in diameter as of midday Monday.
The phenomenon, which is similar to lake-effect snow, is "really quite interesting," said Brian Barjenbruch, science and operations officer for the Weather Service office in Valley. However, he said, "It's not uncommon. The cases I've seen, it takes really specific atmospheric conditions."
And it shows up on radar, just like normal weather and less-common phenomena such as massive insect swarms or smoke from controlled (or uncontrolled) burns.
Weather Service officials noticed Monday's persistent band of snow on radar, and traced the origin by contacting local officials in Norfolk, Barjenbruch said. He didn't know which plants, specifically, were emitting the steam.
The narrow band, which dropped about 2 inches of snow east of Madison by Monday afternoon, was separate from the on-again, off-again precipitation seen in other parts of eastern Nebraska during the day, Barjenbruch said.
The Norfolk snow band lingered much of the day, but was expected to dissipate overnight.
It's been confirmed that this snow band is originating from 2 plants in Norfolk. The steam produced there is essentially acting to add moisture and warmth to the clouds creating the snow. Had reports of large flake and up to 1in. If you live in that area how much have you seen? pic.twitter.com/mSiVcj6uH2— NWS Omaha (@NWSOmaha) December 3, 2018
Much of Nebraska was still dealing with slick conditions as a result of the broader snowstorm over the weekend.
Several accidents were reported Monday morning in Lincoln, including a jackknifed semi on Interstate 80 near mile marker 402, the scanner indicated. Twenty city crews had plowed arterials, bus routes and school routes overnight, applying deicers as needed. But residential streets still were snow- and ice-covered.
The Nebraska State Patrol said it responded to 49 crashes over the weekend and helped 224 motorists.