Cumulonimbus Clouds: Thunderstorms

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Definition: Dark-based storm cloud capable of impressive vertical growth and heavy precipitation

Description & Characteristics. Cumulonimbus clouds are responsible for stormy weather. If you’re looking up at a cloud that’s causing rainy and windy conditions, creating hail, thunder, and lightning, you’re in close proximation of a cumulonimbus cloud.

If you’re observing this cloud from a distance, what will stand out most is the cloud’s impressive height. The cumulonimbus cloud is the only cloud that extends through all three cloud levels. Its base can be very low to the ground, and its top can extend to the highest layer of the troposphere. The top of the cloud might take on a bald appearance (calvus cloud species), or it can take on a hairy and fibrous upper portion (capillatus cloud species).

The more potent cumulonimbus clouds can create a handful of cloud features. Above the main cloud, an anvil cloud (incus cloud feature) can form, where the cloud hits the top of the troposphere and spreads out across the sky. Additionally, you might find the most dramatic examples of mammatus clouds (mamma cloud feature) in the upper portion of a cumulonimbus, caused by pockets of sinking air.

Closer to the ground, cumulonimbus clouds are also responsible for shelf clouds (arcus cloud feature), wall clouds (murus cloud feature), tail clouds attached to the wall cloud (cauda cloud feature), a beaver tail cloud that acts like a river of moisture feeding into the storm (flumen cloud accessory) and even funnel clouds (tuba cloud feature).

Cumulonimbus capillatus incus (Cb cap inc)
Cumulonimbus arcus (Cb arc)
Cumulonimbus murus praecipitatio (Cb mur pra)
Cumulonimbus capillatus incus (Cb cap inc)
Cumulonimbus murus praecipitatio tuba (Cb mur pra tub)
Cumulonimbus tuba (Cb tub)
Cumulonimbus praecipitatio pannus (Cb pra pan)
Cumulonimbus murus (Cb mur)
A photograph of cumulonimbus capillatus incus clouds (Cb cap inc) over a house in a field

Cumulonimbus Cloud Facts

  • Cloud Level (Étage): ….. Low, though it extends into both the middle and high cloud levels
  • Altitude/Height: ……… 0.5-16km (2,000-52,000 ft)
  • Latin Term: …………… Derives from cumulo-, meaning heap, and nimbo-, meaning rain
  • Abbreviation: ………… Cumulonimbus can be abbreviated as Cb
A bar graph showing the visual color of a cumulonimbus cloud

Cloud Color

Light gray to very dark gray

A bar graph showing the precipitation potential of a nimbostratus cloud

Precipitation Potential

Very common, heavy at times

A bar graph showing the amount of sky cover from a cumulonimbus cloud

Sky Cover

Cloudy to partly sunny

A bar graph showing how common observing a cumulonimbus cloud might be

Cloud Frequency

Uncommon

Cumulonimbus Cloud Species

Cumulonimbus clouds have two associated cloud species: calvus and capillatus. Both of these species are unique to cumulonimbus clouds.

A graphical illustration of a cumulonimbus calvus cloud

Cumulonimbus calvus

Without cirriform, hairless

A graphical illustration of a cumulonimbus capillatus cloud

Cumulonimbus capillatus

Fibrous upper portion

Cumulonimbus Cloud Varieties

Roses are red, weather’s integral in our society, but cumulonimbus clouds have no associated cloud varieties. ⛅

Cumulonimbus Cloud Supplementary Features

Cumulonimbus clouds have eight associated supplementary features: arcus, cauda, incus, mamma, murus, praecipitatio, tuba, and virga. The features cauda, incus, and murus are unique to cumulonimbus clouds.

A graphical illustration of a cumulonimbus arcus cloud

Cumulonimbus arcus

Shelf cloud, gust collar

A graphical illustration of a cumulonimbus cauda cloud

Cumulonimbus cauda

Tail cloud, attached to murus

A graphical illustration of a cumulonimbus incus cloud

Cumulonimbus incus

Anvil above a cumulonimbus

A graphical illustration of a cumulonimbus mamma cloud

Cumulonimbus mamma

Sac-like, resembling cow udders

A graphical illustration of a cumulonimbus murus cloud

Cumulonimbus murus

Wall cloud, cloud lowering

A graphical illustration of a cumulonimbus praecipitatio cloud

Cumulonimbus praecipitatio

Precipitation reaching the surface

A graphical illustration of a cumulonimbus tuba cloud

Cumulonimbus tuba

Funnel cloud, tornado

A graphical illustration of a cumulonimbus virga cloud

Cumulonimbus virga

Evaporating rain strips

Cumulonimbus Cloud Accessories & Other Clouds

Cumulonimbus clouds have four associated accessory clouds: flumen, pannus, pileus, and velum. The accessory cloud flumen is unique to cumulonimbus clouds. They also have one other cloud associated with the cloud type: flammagenitus.

A graphical illustration of a cumulonimbus flumen cloud

Cumulonimbus flumen

Beaver tail, detached from murus

A graphical illustration of a cumulonimbus pannus cloud

Cumulonimbus pannus

Ragged frazzles, scud

A graphical illustration of a cumulonimbus pileus cloud

Cumulonimbus pileus

Cap or hood over a cumuliform

A graphical illustration of a cumulonimbus velum cloud

Cumulonimbus velum

Horizontal cloud veil

A graphical illustration of a cumulonimbus flammagenitus cloud

Cumulonimbus flammagenitus

Pyrocumulus, caused from fire

Similar Cloud Types

Cumulonimbus vs. Cumulus

Cumulonimbus clouds fully developed are much different than typical fair-weather cumulus clouds, but a cumulus congestus cloud is the precursor to a cumulonimbus cloud. If you’re trying to decide between the two, and the cloud in question has precipitation, lightning, or a fibrous upper portion, you can consider it a cumulonimbus cloud. Otherwise, you can peg it as a cumulus cloud.

Cumulonimbus vs. Nimbostratus

Both cumulonimbus clouds and nimbostratus clouds have precipitation, and when underneath the two, it might be tough to differentiate the two. If the precipitation is particularly heavy, or if the rain is accompanied by thunder, lightning, or other cloud features like a wall cloud (murus), shelf cloud (arcus), or a tail cloud (cauda), you’re under a cumulonimbus cloud.