FAA Part 107 Drone Practice Test

Which type of clouds typically indicate stable air conditions?

1. Cumulus clouds

2. Stratus clouds

3. Cumulonimbus clouds

4. Cirrus clouds

The correct answer is: Stratus clouds

Stratus clouds are indeed indicative of stable air conditions. These clouds form in layers, often covering the entire sky and resulting in overcast skies that can produce light precipitation. The stable air associated with stratus clouds typically prevents significant vertical development, leading to a more uniform cloud structure and reduced turbulence. This stability often means there is less vertical mixing of air, which allows the clouds to spread out horizontally rather than ascending to create puffy, towering shapes. In contrast, the other types of clouds like cumulus, cumulonimbus, and cirrus clouds generally indicate more active air conditions. Cumulus clouds, for example, signify rising air and can develop into unstable conditions, while cumulonimbus clouds are associated with thunderstorms and turbulent weather. Cirrus clouds often indicate ice crystals at high altitudes and can sometimes predetermine shifts in weather patterns caused by disturbances. Thus, the presence of stratus clouds serves as a clear indicator of stable, calm weather conditions.