Geography: Types of Clouds

High Clouds (mean height 6 to 13 km):

1. Cirrus: do not give precipitation.
2. Cirro-cumulus: Thin, white patch; sheet or layer of cloud;
3. Cirro-stratus: mainly formed of ice-crystals.

Middle Clouds (mean height 2 to 6 km.):

1. Alto-cumulus: composed of super-cooled liquid droplets.
2. Alto-stratus: precipitation may fall either as fine drizzle or snow.
3. Nimbo-stratus: it is a rain, snow or sleet cloud; never accompanied by lightening, thunder or hail.

Low Clouds (mean height 0 to 2 km.):

1. Strato-cumulus
2. Stratus: difficult to differentiate between high fog and stratus.
3. Cumulus: they dissipate at night.
4. Cumulo-nimbus: These clouds are associated with heavy rainfall, thunder, lightning and hail; have flat top and a flat base; it obstructs the sun.