Hail typically forms in which atmospheric conditions?

Hail formation is most commonly associated with strong updraft conditions, typically found in cumulonimbus clouds. These towering clouds, which develop during severe thunderstorms, create intense vertical air movement. In these conditions, warmer air rises rapidly, carrying moisture into the upper parts of the cloud where temperatures are much colder. As the moisture condenses and freezes, hailstones begin to form.

The ongoing updraft keeps the developing hailstones suspended within the cloud, allowing them to grow larger as they collide with supercooled water droplets. These droplets freeze upon contact, adding layers to the hailstone until it becomes too heavy to be supported by the updraft and eventually falls to the ground.

The other options do not create the necessary conditions for hail formation. A stable atmosphere lacks the vigorous lifting needed to form the clouds where hail develops. While warm air with high humidity can contribute to thunderstorms, it is the strong updrafts that are critical for hail. Lastly, calm and clear weather does not produce the severe convective activity required for hail to form.