Cumulonimbus mammatus clouds are unique and beautiful cloud formations that grab a viewer’s attention. If you have seen them, you will remember their unusual pouch-like appearance. Hanging from the bottom of clouds, there are udder shaped protuberances that inspire the name mammatus, from the Latin “mamma” breast.

Cumulonimbus mammatus do not cause severe weather but are often associated with particularly strong, possibly even tornadic storms. Highly turbulent air occurring at the bottom of the clouds forms the odd shaped pouches, which can be opaque or transparent in appearance. They will also vary in size. Mammatus clouds can be composed of liquid, ice, or a combination of both.  

The intense wind shear within the cumulonimbus cloud that produces the mammatus causes this to be a cloud that must be specially remarked in aviation weather reports so that pilots can avoid them. 

Although these clouds can be formed all around the United States, they most commonly form in the middle and eastern states during the warm months of the year.  The photographs above were taken in the summer of 2005, in Lake Charles, Louisiana.

For more information on CUMULONIMBUS, the parent cloud, click here.