Wikipedia:Picture of the day/March 4, 2006
Appearance
Cirrus clouds are composed of ice crystals and appear as hairlike filaments. They are formed at altitudes above 5000 metres (16,500 feet). The streaks are made of snowflakes that are falling from the cloud and being caught by the high level winds. The streaks point in the direction of the wind and may appear straight giving the clouds the appearance of a comma (cirrus uncinus), or may seem tangled, an indication of high level turbulence. Photo credit: Piccolo Namek |