The Cellar - View Single Post - 4/1/2004: Unusual rainbow-cloud

Undertoad · 04-01-2004, 11:04 AM

Copyright and permission Andy Freed, this shot is a pretty rare phenomenon. Discussed on the Earth Sci Pic of the Day and on Mr. Freed's own site entry. It turns out this is "probably a portion of a circumhorizontal arc" which is "a halo phenomenon -- formed by ice crystals usually in cirrus type clouds" and "usually only observed during mid-day in the late spring and summer months (in the mid latitudes) when the Sun attains an elevation greater than about 58 degrees above the horizon."

Pretty cool.

04-01-2004, 11:04 AM	#1
Undertoad Radical Centrist Join Date: Jan 2001 Location: Cottage of Prussia Posts: 31,423	4/1/2004: Unusual rainbow-cloud Copyright and permission Andy Freed, this shot is a pretty rare phenomenon. Discussed on the Earth Sci Pic of the Day and on Mr. Freed's own site entry. It turns out this is "probably a portion of a circumhorizontal arc" which is "a halo phenomenon -- formed by ice crystals usually in cirrus type clouds" and "usually only observed during mid-day in the late spring and summer months (in the mid latitudes) when the Sun attains an elevation greater than about 58 degrees above the horizon." Pretty cool.