Which cloud type is most associated with thunderstorms?

• A. Cirrus
• B. Cumulonimbus
• C. Stratus
• D. Cumulus

Answer: (B)

Thunderstorms come from deep convection, where warm, moist air rises rapidly and cools to form a very tall, dense cloud. The cloud that develops from this vigorous ascent is cumulonimbus—a towering pillar that can stretch high into the upper troposphere and often gains an anvil-shaped top as strong winds spread the upper portion. This name-change from a smaller cumulus to a cumulonimbus signals the intense vertical development needed to produce heavy rain, lightning, thunder, and sometimes hail or tornadoes. Cirrus clouds are high, wispy indicators of moisture high in the atmosphere and don’t produce thunderstorms. Stratus clouds are flat, layered layers that bring overcast skies or light rain, not strong updrafts. Cumulus clouds are the fluffy, fair-weather clouds; they become cumulonimbus only when they grow tall and dark, signaling a thunderstorm.