Which type of cloud is typically formed by strong upward lifting in an unstable atmosphere and can have great vertical extent?

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

Answer: (B)

Strong upward lifting in an unstable atmosphere drives intense convection, causing air to rise, expand, and cool. If the rising parcel remains warmer than its surroundings, it keeps rising and clouds grow rapidly with great vertical extent. This produces cumulonimbus clouds, which can reach high into the troposphere and are often linked to thunderstorms and severe weather.

Cirrus clouds, by contrast, form high, thin wisps of ice crystals with little vertical growth and no thunderstorm activity. Stratus clouds are low, flat layers that produce overcast skies and light drizzle, not tall, vertical development. Nimbostratus are thick, widespread rain clouds at lower levels without the strong, towering vertical reach of cumulonimbus.