The lightning can be so frequent and bright ... a formation of clouds so unique that they seem otherworldly. Mammatus clouds, with their characteristic pouch-like protrusions, typically form ...

Formed by cold air sinking down, mammatus clouds are usually seen when there is turbulence in a cumulonimbus cloud. Two astronauts are returning home after nine months in space. Nick Beake of the ...

These globular clouds usually form underneath the base of a cumulonimbus cloud and are associated with strong thunderstorms. The globular lobes clump together to form small patches that last only ...

These clouds are often associated with thunderstorm clouds and accompanied by rain, hail and lightning. Mammatus is most often found at the base of a thunderstorm cloud called cumulonimbus.

These clouds are often associated with strong wind gusts and heavy rain, but can occasionally produce a brief tornado. Mammatus clouds are some of the most photographed clouds because of their odd ...