Cirrus Clouds from above around 20000 feet (6000 metres). There are primarily composed of ice crystals due to the cold temperatures at this height and are typically white in colour. At sunrise and sunset, however, they can reflect unscattered components of sunlight (red, orange and yellow).

A phenomenon associated with cirrus clouds is "fall streaks." These are formed when ice crystals or snow forms in cirrus and fall from the cloud with typical speeds of 1 to 8 m/s. Fall streaks tend to stretch horizonally as well as vertically.