Stable air is typically indicated by which cloud type?

• A. Stratiform clouds
• B. Cumuliform clouds
• C. Cirrus clouds
• D. Cumulonimbus clouds

Answer: (A)

Stable air suppresses vertical motion, so moisture tends to condense in broad horizontal layers rather than tall, rising columns. That creates stratiform clouds, which are flat or sheet-like, covering large areas with little vertical development. This smooth, layered appearance reflects a gentle, widespread lifting process and a stable environment. In contrast, clouds with significant vertical growth—cumuliform and especially cumulonimbus—signal air that’s unstable and prone to convection, while cirrus clouds are high and wispy and don’t by themselves indicate stability. So the cloud type most typical of stable air is stratiform.