cloud types

Tallest of all clouds, may extend to over 18,000 m (60,000 ft). Appear as mountains or high towers. Usually have large anvil-shaped tops of ice.

The lowest clouds, often appear as an overcast deck but can be scattered patches. Individual cloud elements have very ill-defined edges.

Very dark, low clouds associated with large areas of continuous precipitation. Although bases are usually low, their vertical extent often extends well into the middle cloud region.

Low clouds with elements in tight clusters and very little vertical development. Relatively flat lacking the sharp edged, popcorn appearance of cumulus clouds.

Mid-level clouds with uniform and diffuse coverage where it is difficult to detect individual elements or features. Grey or bluish in colour.

Mid-level clouds whose distinct cloud elements are either a sheet or a patchy deck with waved bands, rolls, or rounded masses. Elements usually sharply outlined.

High clouds composed of ice crystals in the form of delicate filaments, patches or bands.

High clouds with ice particles forming a transparent cloud veil of fibrous or smooth texture, partially or totally covering sky.

High ice clouds composed of small elements in form of separated patches, ripples, fish scales etc., more or less regularly arranged.

Small heap clouds with flat bottoms and slightly rounded tops that extend through mid-level to high altitudes.

Heap clouds of both great vertical and horizontal extent, looking like a cauliflower. Bottoms sharp; tops rounded with sharp outline. Extend through mid-level to high altitudes.

Heap clouds of great vertical extent, looking like a castle tower. Bottoms sharp; tops rounded with sharp outline.

Often saucer-shaped, they form in the crests of atmospheric waves, commonly occurring as air passes over high mountain peaks.

Ice clouds forming transparent cloud veil at altitudes above 80 km (50 miles), so thin stars can often shine through.

Mother-of-Pearl clouds. A stratospheric ice cloud formed at altitudes of 15-30 km (10-20 miles). They are the polar stratospheric clouds associated with ozone destruction

• STRATUS
• The lowest clouds, often appear as an overcast deck but can be scattered patches. Individual cloud elements have very ill-defined edges.

• NIMBOSTRATUS
• Very dark, low clouds associated with large areas of continuous precipitation. Although bases are usually low, their vertical extent often extends well into the middle cloud region.

• STRATOCUMULUS
• Low clouds with elements in tight clusters and very little vertical development. Relatively flat lacking the sharp edged, popcorn appearance of cumulus clouds.

• ALTOSTRATUS
• Mid-level clouds with uniform and diffuse coverage where it is difficult to detect individual elements or features. Grey or bluish in colour.

• ALTOCUMULUS
• Mid-level clouds whose distinct cloud elements are either a sheet or a patchy deck with waved bands, rolls, or rounded masses. Elements usually sharply outlined.

• CIRRUS
• High clouds composed of ice crystals in the form of delicate filaments, patches or bands.

• CIRROSTRATUS
• High clouds with ice particles forming a transparent cloud veil of fibrous or smooth texture, partially or totally covering sky.

• CIRROCUMULUS
• High ice clouds composed of small elements in form of separated patches, ripples, fish scales etc., more or less regularly arranged.

• CUMULUS HUMILIS
• Small heap clouds with flat bottoms and slightly rounded tops that extend through mid-level to high altitudes.

• CUMULUS CASTELLANUS
• Heap clouds of great vertical extent, looking like a castle tower. Bottoms sharp; tops rounded with sharp outline.

• CUMULONIMBUS
• Tallest of all clouds, may extend to over 18,000 m (60,000 ft). Appear as mountains or high towers. Usually have large anvil-shaped tops of ice.