Arctic Air Mass Creates Light Pillars And Sundogs Around Colorado

DENVER (CBS4) - It's no question that bitter cold air from the arctic can pose a wide range of danger when it invades a region, but there's also a beautiful side to it as well. When ice crystals form in this very cold air, they take on the shape of plates, columns and needles, instead of the more commonly known dendrite, or the snowflake.

In addition, because very cold air is dense, it hangs close to the ground, creating a very low cloud deck. As ice crystals in these clouds interact with terrestrial lights from the surface at night, our eye sees tall columns, or pillars, or light.

Even if the sky is clear, tiny suspended ice crystals can still create very cool light displays, even during the day. The picture below shows sundogs shining over Denver just after sunrise on Thursday.

Sundogs are spots of light on either side of the rising or setting sun. The light is created by the refraction of sunlight shining though ice crystals suspended in the air. Sundogs are found roughly 22 degrees to either the left or right of the sun.

The colors in a sundog usually go from red closest to the sun, to blue on the outer edge. Sundogs are also known as mock suns, or parhelia.