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Earth and Space > Cloud Types

The following table shows a variety of cloud types, general appearances and altitudes.

Type of Cloud (Genus) Abbreviation Appearance Composition Altitude (height)
Cumulo-nimbus Cb Can cause lightning, thunder, hail, strong rains, strong winds, and tornadoes. Dark and massive in appearance.   Near ground up to 75,000 feet
(Vertical clouds)
Cirro-stratus Cs Thin, wispy, appears in sheets. Located above Cumulo-nimbus.   Above 18,000 feet
(High-altitude clouds)
Cirrus Ci Thin, wispy, sometimes curly. Mostly composed of ice crystals Above 18,000 feet
(High-altitude clouds)
Cirro-cumulus Cc Small, puffy, patchy sometimes with a wavelike appearance   Above 18,000 feet
(High-altitude clouds)
Alto-cumulus Ac Medium-sized puffy, patchy, scattered clouds - often in linear bands   6,500 - 20,000 feet
(Middle-altitude clouds)
Alto-stratus As Thin, uniform   6,500 - 20,000 feet
(Middle-Altitude clouds)
Strato-cumulus Sc Broad and flat on the bottom, puffy on top,   Below 6,500 feet
(Low-altitude clouds)
Cumulus Cu Puffy and piled up.   Below 6,500 feet
(Vertical clouds)
Stratus St Uniform, flat, thick to thin layered clouds with non-defined edges Mostly composed of liquid droplets Below 6,500 feet
(Low-altitude clouds)
Nimbo-stratus Ns Uniform, dark, flat, low, featureless clouds that produce precipitation Mostly composed of liquid droplets Below 6,500 feet
(Low-altitude clouds)
Fog Very low stratus clouds   Mostly composed of liquid droplets In contact with the ground.