Cirrostratus

A Cirrostratus is a cloud belonging to a class characterized by a composition of ice crystals and often by the production of halo phenomena. It appears as a whitish and usually somewhat fibrous veil, often covering the whole sky and sometimes so thin as to be hardly discernible. These clouds are of high altitude (20,000-40,000 ft or 6000 -12,000 m).

External Links

• National Science Digital Library - Cirrostratus (http://www.nsdl.arm.gov/Library/glossary.shtml#Cirrostratus)