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Types of Cloud

Part of Weather For Dummies Cheat Sheet

Clouds play a large role in discussing, predicting, and watching the weather — not to mention providing scope for daydreams and flights of fancy. The following list describes the common cloud types that form in various layers of the atmosphere — their names and what they look like — as well as clouds that form vertically.

  • High layered (above 17,000 feet):

    • Cirrus: Delicate white strands of ice crystals, often forming “mares tails.”

    • Cirrostratus: A veil of white cloudiness often covering the entire sky, causing “halos” around the moon and Sun and frequently indicating an approaching storm.

    • Cirrocumulus: Small white patchy patterns like fish scales and often called “mackerel skies.”

  • Middle layered (6,000 to 17,000 feet):

    • *Altostratus: Drab gray clouds of water droplets that obscure the image of the sun or moon. They can produce rain and snow.

    • Altocumulus: A darker, larger pattern of patchiness that may produce a shower.

  • Low layered (below 6,000 feet):

    • Stratus: Wispy cloud of fog that hangs a few hundred feet above the ground, often bringing drizzle.

    • Stratocumulus: Dark gray clouds, often covering the entire sky, which usually do not rain. They form rounded wavelike bands that are broken by blue sky.

    • Nimbostratus: Low, dark, ragged rain clouds that often bring continuous rain or sleet or snow.

  • Vertical clouds:

    • Cumulus: Large, billowy “cotton balls” of clouds with dark bottoms and bright white tops that can reach 10,000 feet high. May produce brief showers.

    • Cumulonimbus: Towering thunderheads, dark on the bottom and white anvil-shaped tops that can extend to 50,000 feet. Often produces lightning and heavy precipitation, including hail, and occasionally tornadoes.