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What Type of Cloud Produces Rain?

Clouds come in a variety of shapes and sizes, generally categorized by meteorologists as "families." Cloud families included cirrus, cumulus and stratus, distinguished by their shapes. Clouds have designations that refer to their general altitude, starting with the highest cirrus clouds and ending with the middle alto clouds. They can form in any variation. The most common thunder clouds or rain clouds can be a combination of two cloud types and produce drizzle, fog and precipitation.

  1. General Cloud Condition

    • Clouds, whatever their type or altitude, must have some density for them to hold water molecules. To hold moisture, clouds must have some amount of dirt in them, such as airborne dust, smoke or salt. Even the cleanest-appearing white clouds hold enough microscopic dirt particles to hold water molecules and produce rain. Water can accumulate inside a cloud during sunny or overcast conditions.

    Cumulonimbus

    • Cumulus clouds have billowy bloblike shapes, with smooth, flat bases. They form during sunny or overcast days and can have the same height and width dimensions. When they accumulate in the middle or high altitude parts of the atmosphere and take on a darkened hue, it means they have accumulated great amounts of water. Cumulus clouds that form tall and dark profiles, as a result of pockets of rising air, turn into cumulonimbus clouds. Cumulonimbus clouds can let loose with a thunderstorm, producing great sheets of rain, hail and lightning. Fast-moving cumulonimbus clouds frequently produce tornadoes.

    Nimbostratus

    • Stratus clouds usually appear in layers and cover much of the sky. They look relatively thin compared to their great width. When they form puffy globs, they become stratocumulus clouds. When stratocumulus clouds become thick and dark, they transform into nimbostratus clouds, their heaviest and darkest structure. Nimbostratus clouds often produce rain and snow and have the potential to create severe thunderstorms.

    Altocumulus

    • Altocumulus clouds generally appear at lower levels in sheetlike layers, but they can rise and accumulate moisture. Upon saturation, altocumulus clouds become bunched up or appear in fluffy, dark waves; then they can bring drizzle, light rain or heavy downpours.

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