Clouds are usually classified by height into low, middle, and high. Low clouds, which form from ground level up to about 2000 metres, include stratus, cumulus, cumulonimbus, nimbostratus, and stratocumulus. Middle clouds, which form between 2500 and 6000 metres, include altostratus and altocumulus. High clouds, which form above 6000 metres and up to about 10 600 metres, include cirrocumulus, cirrostratus, and cirrus.
Subjects: Environmental Science.