As mentioned in the video and seen in the picture, the strange looking rainbow surrounding the glowing sun is called a sun dog*. Sure it has all the same colors as a traditional rainbow, but due to the process at which its forms it may be more accurate to call it…an icebow. We’ve talked about ice crystals before, and in this situation they are the most important ingredient when forming the colorful circle that looks to be encompassing the sun. The ice crystals are located high up in the atmosphere, where temperatures are a far from pleasing -15°F.
Here cirrus clouds don’t use water droplets to get their shape, instead, they use tiny ice crystals to give them their free flowing, wispy look. Combine the ice crystals with just the right angles between the sun, ice and your eyes and Viola! you have yourself a very rare, and very cool event. Even better, the same ingredients can be used at night, just replace the sun with the moon and you have yourself a…you guessed it…moon dog!
We’ll forget about the protractors today and just mention that as the sun lifts higher into the sky, the circle around the sun will actually grow out (so long as the ice crystals are still in place). The best time to see these “dogs” are when the sun/moon are low in the sky.
Interestingly, a minor league hockey team in Arizona has used the icy nature of this event to identify their team as the Arizona Sundogs. Hopefully their victories are a little bit more common than the actual phenomenon though.
In the past Native Americans have used sun (moon) dogs to help predict the coming of rain. From a meteorological perspective this makes perfect sense. High cirrus clouds that are always found accompanying this phenomenon often resemble dry, calm conditions. In a couple of days, this calm stable air will be replaced by an unstable air mass with more moisture closer to the ground (Better rain chances). Putting it altogether, it could be reasoned that seeing this phenomenon could mean rain in the coming days. That being said, I wouldn’t mind capturing one of these dogs to help out with our drought situation :-)
Thank you to Anke Cahoon for the picture!
*The harder to pronounce, thus more scientific name of this feature is known as a “Parhelion”