Solar Halo Observed Over Elk Grove, Illinois

February 02, 2016

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Photographer: Julio Guerrero
Summary Authors: Julio Guerrero; Jim Foster
 
This spectacular 22 degree solar halo was staring me right in the face when I looked outside on the morning of January 21, 2016, in Elk Grove, Illinois. What a pleasant way to start a midwinter's day; much better than being greeted by a furry rodent with dubious forecasting skills. This halo was visible for an hour — from about 8 to 9 a.m.

The 22 degree halo forms when sunlight is refracted in randomly oriented, pencil-shaped ice crystals. Light passes through one of the side faces of these crystals and is bent 22 degrees before exiting through an alternate side face. Note the upper tangent arc at the very top of the halo.