Mamma Cloud Feature:Sac-Like, Resembles Cow Udders

Learn all about mammatus clouds (mamma), including pictures and images of their various characteristics, how to identify them, and more.

Cumulonimbus incus mamma (Cb inc mam)
Cumulonimbus incus mamma (Cb inc mam)

Identifying the mammacloud feature

A popular cloud feature resembling cow udders better known as mammatus clouds

Popularly known in the weather community as mammatus clouds, the ‘mamma’ cloud feature can be found amongst six cloud types: cirrus, cirrocumulus, altocumulus, altostratus, cumulonimbus, and stratocumulus. Translated from latin, meaning breast, the six types of mamma clouds are respectively abbreviated as ‘Ci mam’, ‘Cc mam’, ‘Ac mam’, ‘As mam’, ‘Cb mam’, and ‘Sc mam’. Mamma cloud formations are condensed pockets of sinking air that look like cow udders lowering from the base of the cloud.

Even though it was once thought that tornadoes formed from them, mammatus clouds aren’t inherently dangerous. They are commonly found in the vicinity of thunderstorms however. Mammatus clouds are formed the same way cumulus clouds are formed, but in reverse.

They are formed by sinking cold air that form pouch-like figures as they’re carried into a warmer layer of air, contrary to the puffs of clouds rising through the convection of warm air. While they aren’t particularly rare, mammatus clouds can be eye-catching and picturesque, especially at sunset. If you’re a cloudspotter looking for mammatus clouds, pay particular attention to the underside of a thunderstorm’s anvil cloud (incus cloud feature) to increase your chances of spotting them.

Mamma and its cloud types

Mamma can modify each cloud type shown below. Compare how the same term appears across different levels and broader cloud forms.

Compare mamma with related supplementary features

Use the defining shape, arrangement, associated cloud type, and full sky context before selecting the most appropriate term.

Mamma vs. asperitas

Both can create a dramatic cloud underside. Mamma forms distinct rounded or pouch-like lobes, while asperitas spreads into a broader, rough, wave-like surface.

Illustration of mamma clouds
Mamma
Illustration of asperitas clouds
Asperitas
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