What is a characteristic of stable air?

• A. Stratiform clouds
• B. Cumuliform clouds
• C. Thunderstorms
• D. Turbulent air

Answer: (A)

Air stability means vertical motion is resisted; when a parcel is displaced upward, it tends to return to its original level rather than keep rising. That suppression of vertical development leads to widespread, layered cloud formations rather than tall, towering ones. Those layered, horizontally extensive clouds are stratiform clouds, which is why this option best reflects stable air.

Cumuliform clouds form with stronger vertical motion found in unstable air, not stable conditions. Thunderstorms require significant instability and moisture to drive intense vertical development, which isn’t typical of stable air. Turbulent air usually accompanies instability or wind shear, rather than the smooth conditions associated with stability.