Sundogs are commonly made by the refraction of light from plate-shaped hexagonal ice crystals in high and cold cirrus clouds or, during very cold weather, these ice crystals are called diamond dust, and drift in the air at low levels. These crystals act as prisms, bending the light rays passing through them with a minimum deflection of 22°. If the crystals are randomly oriented, a complete ring around the sun is seen — a halo. But often, as the crystals sink through the air, they become vertically aligned, so sunlight is refracted horizontally — in this case, sundogs are seen.
Today as the morning after the storm. There was a bit of snow fallen, but as usual in North Dakota, The problem is always the wind as it shifts the lay of the grainy powder. Most of our driveway was clear with some areas of about 3 inches along it, except near our Garage door. Because my truck was parked there, the blowing snow got caught in between the house, truck, and garage. We had a drift about a foot high stretching out maybe 10 - 15 feet. This required my shoveling it down so we could drive out. Once out, all was well as we ventured to the store and back.
It was a clear and therefore cold day today. Cold icy air after a storm like that is perfect for bringing the ice crystals that create sundogs. It was very pretty but of course, it was very cold with a windchill of -13.
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