Which cloud type is most commonly associated with severe weather phenomena?

Cumulonimbus clouds are the correct answer, as they are the primary cloud type associated with severe weather phenomena such as thunderstorms, heavy rainfall, hail, tornadoes, and severe turbulence. These towering clouds typically have a significant vertical development, reaching great heights in the atmosphere. The structure of cumulonimbus clouds allows them to hold large quantities of moisture, which can lead to intense precipitation and strong downdrafts.

Within these clouds, various processes occur that contribute to severe weather conditions. For instance, the updrafts can create powerful storms, while the anvil shape at the top of the cloud can indicate the potential for severe weather extending over a wide area. Additionally, the presence of an overshooting top can signal the strength of the convection occurring within the cloud, which is often a precursor to severe weather events.

Stratus clouds are generally associated with overcast conditions and light precipitation, but they do not produce severe weather. Nimbostratus clouds are also associated with steady, light to moderate rain and do not typically reach the vertical extent necessary to produce severe weather. Cirrus clouds are high-altitude clouds that usually indicate fair weather and do not contribute to severe weather phenomena either. Thus, cumulonimbus clouds are uniquely positioned as the type