Which cloud type is most likely to experience moderate to severe turbulence?

Cumulonimbus clouds are associated with severe weather conditions and are the primary cloud type that can produce moderate to severe turbulence. These towering clouds extend high into the atmosphere and are often linked with thunderstorms, lightning, and heavy precipitation. The vertical development of cumulonimbus clouds creates strong updrafts and downdrafts within the cloud structure, leading to significant turbulence both within the cloud and in its vicinity.

The turbulence is often exacerbated by the processes occurring inside the cloud, such as rapid changes in wind speed and direction, which can create shear layers that pilots must be cautious of. Pilots are particularly advised to avoid areas of active cumulonimbus clouds when flying due to the potential for encountering turbulence as well as severe weather phenomena. In contrast, the other cloud types mentioned tend to have more stable characteristics and are less likely to produce the severe turbulence associated with cumulonimbus.