Mammatus (also called mamma [1] or mammatocumulus, meaning "mammary cloud") is a cellular pattern of pouches hanging underneath the base of a cloud, typically a cumulonimbus raincloud, although they may be attached to other classes of parent clouds.

Apr 27, 2022 · They are a specific form of stratocumulus, altocumulus, or cirrocumulus clouds. These clouds form around mountains, hills, and buildings and resemble UFOs. Mammatus clouds are cumulus clouds (usually cumulonimbus) with cellular pouches hanging from the cloud base.

Feb 20, 2025 · Mammatus clouds are actually altocumulus, cirrus, cumulonimbus, or other types of clouds that have these pouch-like shapes hanging out of the bottom. The pouches are created when cold air within the cloud sinks down toward the Earth.

Oct 1, 2006 · German meteorologists in the early twentieth century also recognized that mammatus clouds could occur in association with altostratus, altocumulus, and cirrus. Scorer (1972) noted that mammatus can occur on falling rain or snow below a cloud base or on streaks of falling ice crystals.

Altocumulus clouds are small patches of mid-level clouds and represent cool, non-turbulent weather. The altocumulus cloud's composition includes ice and water. There are various types and sizes of altocumulus 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.

Nov 30, 2023 · Although they are often associated with cumulonimbus anvil, which are essentially giant masses of unstable air, mammatus can occasionally form in other types of clouds like stratocumulus, altostratus and altocumulus. Mammatus clouds sometimes also form on the underside of volcanic ash clouds.

Mammatus are most often associated with anvil clouds and also severe thunderstorms. They often extend from the base of a cumulonimbus, but may also be found under altocumulus, altostratus, stratocumulus, and cirrus clouds, as well as volcanic ash clouds.

While altostratus is often flat and featureless, altocumulus usually creates interesting and varied skies. In some cases, many thousands of small altocumulus clouds will be strung together across the sky in spectacular formations.

Feb 3, 2013 · Mammatus are pouch-like cloud structures. They're also a rare example of clouds in sinking air-- most clouds form in rising air. Although mammatus most frequently form on the underside of a...