Cloud Classification - Types, Pictures, & Info

High Level Clouds

Including cirrus, cirrocumulus, and cirrostratus. Highest levels of the atmosphere; Consist of ice droplets because of their altitude in the atmosphere.

Middle Level Clouds

Including altostratus, altocumulus, and stratocumulus. Middle levels of the atmosphere; Consist of water droplets, some frozen; Rarely produce precipitation.

Low Level Clouds

Including cumulus, cumulonimbus, and nimbostratus. Lowest levels of the atmosphere; Some of these low level clouds produce rain, thunderstorms; Appear more thick and puffy than most other clouds.

High Level Clouds
Cloud type	Elevation (km)	Description
	5 or +	In their curly form, these clouds usually cover only parts of the sky and consist of ice droplets (in winter they may form at the surface in the form of fog); The precipitation is in the form of snow or ice, but they usually melt from warmer temperatures in the lower atmosphere, and this creates their curly look.
	6 or +	These clouds usually cover large areas of the sky and have no real definite shape; They're made up of tiny ice crystals and can sometimes produce a halo around the sun.
	8 or +	These clouds usually cover only parts of the sky and can be a sign of high level turbulence; They don't usually stay in one place for very long and appear to be patchy from the winds.

Middle Level Clouds
Cloud type	Elevation (km)	Description
	3 - 6	These clouds can be a sign of an approaching warm front; Made up mostly of water droplets; They don't have any distinguishing shapes or features.
	2 - 3	These clouds are similar to those of cumulus; They can be a sign that the air has a lot of moisture, but not a significant amount of turbulence.
	1 1/2 - 5	These clouds are a sign of warm air rising; They often occur in advance of an approaching storm and are made mostly of water droplets.

Low Level Clouds
Cloud type	Elevation (km)	Description
	1 - 2	These clouds are the lowest clouds that produce precipitation; Usually block the sun; Form dark, thick layers close to the Earth's surface; Depending on the temperature they can be made up of water droplets or ice droplets.
	1 - 6	These are the tallest of all clouds and can produce rain, hail, severe storms, and even tornados; These clouds can have an anvil, which indicates the instability of the air; Only these clouds can produce lightning and tornados; They're made up ice crystals high in the atmosphere and water closer to the base of the cloud.
	2 - 5	These are fair weather clouds that usually form at low altitudes, are made of water crystals, but the taller ones can have ice above them in the higher levels of the atmosphere.