Which type of clouds is known to cause the greatest turbulence?

Cumulonimbus clouds are known for causing the greatest turbulence due to their vertical development and the intense weather phenomena associated with them. These clouds are capable of reaching high altitudes and are often associated with severe weather conditions, including thunderstorms, heavy precipitation, and strong updrafts and downdrafts.

The structure of cumulonimbus clouds allows for significant vertical air movement, which can create turbulent conditions in the atmosphere. The violent air currents within these clouds make them particularly hazardous for flight, as they can lead to sudden and severe changes in altitude and airspeed.

In contrast, other cloud types like stratus and altostratus are more stable and are generally associated with overcast skies and light precipitation, which do not generate the same level of turbulence. Cumulus clouds, while they can produce some turbulence, are typically not as severe compared to cumulonimbus and are more associated with fair weather. Cumulonimbus clouds stand out due to their ability to produce severe weather and significant turbulence, making them the cloud type to watch for during flight operations.