At what height are cirrus clouds generally found?

Correct answer: At about 6 to 13 km altitude

Correct answer: A, about 6 to 13 km. Cirrus clouds are high-level clouds. They are usually thin, white, and hair-like or feathery in appearance, and because of the very low temperature at great heights, they are mainly made of ice crystals. A is correct because the commonly taught general altitude range for cirrus is approximately 6–13 km, although the exact height can vary with latitude and weather conditions. B represents a middle-level range more often associated with clouds such as altostratus or altocumulus. C describes the lower atmosphere, where low clouds commonly occur. D is impossible for ordinary clouds because clouds form within the atmosphere above the ground. Memory cue: cirrus means high, thin, and icy.