June 2022

A Festoon of Mamma Clouds

These dramatic lobes of cloud are known as mamma. They are features that can form on the underside of a cloud layer and appear as pouches extending downwards into the clear air below. These ones were spotted by Teresa Mardis (Member 29,603) over Stillwater, Oklahoma, US after an evening of severe thunderstorms.

While mamma can form on the underside of several of the ten main cloud types, the best examples are found beneath the storm cloud, Cumulonimbus. That is the one that can unleash lightning bolts and heavy hail showers. Mamma form on the spreading canopy, likened to the shape of a blacksmith’s anvil, up at the top of this mighty beast of the cloud world.

The distinctive lobes develop in pockets of sinking air within the upper part of the storm. While they tend to appear in the vicinity of unsettled weather like this, mamma are not necessarily harbingers of storms to come. The features often seem to develop to the rear of the storm’s movement, and so they mamma can in fact herald a change of conditions from stormy to calm.

Before gaining their Latin classification, mamma were known by some as ‘festooned clouds’. They’re a celestial decoration left by a departing storm – perhaps to remind us that the worst has past and the best is yet to come.

Mamma spotted over Stillwater, Oklahoma, US by Teresa Mardis (Member 29,603).

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