Ice Crystals/Cirrus Optics
January 15, 2010

A deep layer of ice crystals, along with a thin layer of cirrus, over the Sioux Falls area on 15 January 2010, caused multiple optical phenomena in the sky over the region, as pictured below.  Click any of the images below to enlarge.

Photos of a halo and other optical phenomena around the sun,
caused by multiple layers of ice crystals and/or cirrus clouds

 Photo of a partial halo and other optical phenomena around the sun, caused by multiple layers of ice crystals and/or cirrus clouds.

 Photo of a partial halo and other optical phenomena around the sun, caused by multiple layers of ice crystals and/or cirrus clouds.

 Photo of a halo and other optical phenomena around the sun, caused by multiple layers of ice crystals and/or cirrus clouds

The deep layer of ice crystals across the region followed a prolonged period of dense fog early on the morning of 15 January 2010, which resulted in a layer of hoar frost on trees and other surfaces across the area.

Photos of hoar frost which resulted from dense fog across the area earlier in the morning

Photo of hoar frost which resulted from dense fog across the area earlier in the morning Photo of hoar frost which resulted from dense fog across the area earlier in the morning

 


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