Tag Archive | halo

Circumhorizontal Arc – Rainbow Halos!!

These rainbows aren’t made from raindrops…
wpid-20130914_133917.jpgFor a Circumhorizontal arc (CA) to be visible, the Sun must be at least 58 degrees high in the sky and where cirrus clouds are present. Additionally, the copious, flat, hexagonal ice-crystals that compose the cirrus cloud must be aligned horizontally to properly refract sunlight in a collectively similar manner. In principle, a CA is a type of halo. These happen a few times a year here in the Midwest. Other lower latitudes don’t get to see these at all.wpid-20130914_133913.jpgwpid-20130914_133923.jpg