An arctic air mass surging south and east across the western United States aided in creating in rare form, light pillars over a Wyoming city Friday night.
The National Weather Service (NWS) reported Saturday that light pillars formed around midnight, creating a spectacular scene over the city of Laramie.
A light pillar is a visual phenomenon created by the reflection of light from ice crystals with near horizontal parallel planar surfaces.
The light can come from the sun (usually at or low to the horizon) in which case the phenomenon is called a sun pillar or solar pillar. It can also come from the moon or from terrestrial sources such as streetlights, which was the case Friday night.
According to the NWS, the temperature was down around zero at the time with ice fog hovering over streetlights, creating the light pillars over the city. The temperature bottomed out at a frigid 14 degrees below zero early Saturday in what was the coldest air mass of the season for the region so far this winter.
The NWS posted a photo of the light pillars it received from Jaclyn Ritzman, a master's student at the University of Wyoming studying Atmospheric Science.
While light pillars are not a common phenomenon, Niagara Falls is one such area that sees them frequently during the winter months. The city sits in a perfect environment, where cold air masses cause the moisture from the Falls to form ice crystals, which interact with the city's many upward facing spotlights, to create prominent light pillars.
Light pillars have also been known to produce false UFO reports.