Mammatus Clouds

weather · clouds · storms · sky patterns

Pouches from above. Mammatus clouds look like dozens of soft, droopy pillows hanging down from the underside of a cloud. They get their name from the Latin word 'mamma,' which means breast, because of their bumpy, rounded shape.

Born from storms. These amazing clouds usually form under cumulonimbus clouds, which are the huge thunderstorm clouds that bring heavy rain and sometimes hail. The pouches can also attach to other types of clouds, but storms are where they shine.

Signs of turbulence. Mammatus clouds form when there's lots of movement and churning in the air, especially cold air sinking beneath warmer air. They tell you that powerful weather patterns are happening up in the sky.

Rare and stunning. While not super common, when mammatus clouds do appear, they create one of nature's most dramatic and beautiful sky shows. People often stop and stare when they spot these bumpy clouds rolling overhead.

Tricky to predict. Scientists still study mammatus clouds to better understand how air moves inside storm clouds. These pouches help them learn more about how storms develop and change.