cumulonimbus

American  

[kyoo-myuh-loh-nim-buhs] / ˌkyu myə loʊˈnɪm bəs /

noun

Meteorology.

plural

cumulonimbus

1. a cloud of a class indicative of thunderstorm conditions, characterized by large, dense towers that often reach altitudes of 30,000 feet (9,000 meters) or more, cumuliform except for their tops, which appear fibrous because of the presence of ice crystals: occurs as a single cloud or as a group with merged bases and separate tops.

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cumulonimbus British  

/ ˌkjuːmjʊləʊˈnɪmbəs /

noun

1. meteorol a cumulus cloud of great vertical extent, the top often forming an anvil shape and the bottom being dark coloured, indicating rain or hail: associated with thunderstorms

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cumulonimbus Scientific  

/ kyo̅o̅m′yə-lō-nĭm′bəs /

plural

cumulonimbi

1. An extremely dense, vertically developed cloud with a low, dark base and fluffy masses that tower to great heights. Cumulonimbus clouds usually produce heavy rains, thunderstorms, or hailstorms.

2. Also called thundercloud

3. See illustration at cloud

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Etymology

Origin of cumulonimbus

First recorded in 1885–90; cumulo- + nimbus

Example Sentences

Lightning is one of the biggest risks, but it is not only the natural lightning from a thunderstorm - or cumulonimbus cloud - that forecasters will be concerned about.

From BBC

And you won't find more violent up and downdrafts than in cumulonimbus, or thunderstorm clouds.

From BBC

Mammatus is most often found at the base of a thunderstorm cloud called cumulonimbus.

From BBC

Convective - up and down drafts in and surrounding thunderstorm clouds, called cumulonimbus.

From BBC

Thunderstorms are powerful and complex phenomena, with air inside a cumulonimbus storm cloud moving rapidly upwards and downwards.

From BBC