mellowyellow
Well-known Member

Photographer: Eric Maltz
These eye-catching mammatus clouds appeared just after a turbulent, late afternoon thunderstorm moved through Berlin, Germany, on March 11, 2021. The pouches form when colder air moving downward within the cumulonimbus cloud structure pushes into the storm's cloud base. Mammatus are more often seen following a severe storm than preceding it.
I have never seen these clouds, maybe they don't come down to our part of the world.