Rare Winter Phenomenon: Sundog

A Sundog is a rare phenomenon that forms when sunlight is reflected and refracted by ice crystals in the air similar to rainbows. Technically it is actually still a rainbow because the light must pass through water droplets in the air and then split to form the spectrum. This phenomenon goes by a few names like Snowbow, Halos, and Sun Pillars.

Here are the differences, according to the National Weather Service:

Snowbow, is a rare phenomenon that forms when sunlight is reflected and refracted by ice crystals in the air.
Sundogs, also known as mock suns or parhelia, appear as “colored spots of light” at 22 degrees on either side or both sides of the sun, “depending on where the ice crystals are present.”
Halos are white rings “around the sun or moon as the sun or moon light refracts off ice crystals present in a thin veil of cirrus clouds.”
Sun pillars resemble shafts of light “extending vertically above the sun,” usually before dawn or dusk. “They develop as a result of ice crystals slowly falling through the air, reflecting the sun’s rays off of them.”

Although rare, it’s worth looking back after finishing a run, because you never know what kind of beautiful scenery might be behind you!