Cumulonimbus clouds

Symbol: Cumulonimbus cloud symbol

Height of base: 1,100 - 6,500 ft

Shape: Fibrous upper edges, anvil top

Latin: cumulus - heap; nimbus - rainy cloud

Precipitation: Heavy rain and thunderstorms

Cumulonimbus cloud (Photo: Matthew Clark)

Cumulonimbus are heavy and dense low-level clouds, extending high into the sky in towers, plumes or mountain shaped peaks. Commonly known as thunderclouds, the base is often flat and very dark, and may only be a few hundred feet above the Earth's surface. Cumulonimbus clouds are associated with extreme weather such as heavy torrential downpours, hail storms, lightning and tornados.

If there is thunder, lightning or hail, it's a cumulonimbus cloud rather than nimbostratus.

Similar clouds

  • Cumulus
    The fluffy, cauliflower-shaped cumulus are one of the most common and distinctive types of cloud. All cumulus clouds develop because of convection.

  • Stratocumulus
    Stratocumulus clouds consists of large, rounded masses of stratus that form groups, lines or waves.

  • Stratus
    Stratus clouds tend to be featureless, low altitude clouds that cover the sky in a blanket of white or grey.

Last updated: 7 August 2014