Cumulus (Cu)


Personal Photo

Level: Base below 6,500 ft., but extend upward several hundred to several thousand feet

Composition: Water

Typical Conditions: Fair weather but an unstable atmosphere. If more significant instability develops or a capping inversion is removed, some of the cumulus clouds may develop into cumulonimbus, as is often the case as afternoon heating occurs on a warm, humid day.

Appearance: Fluffy, cotton-ball-like shape with white to light gray color. Frequently scattered throughout the sky on an otherwise clear day. If vertical development becomes significant with a well-defined, "bubbling" top but significant precipitation is still not occurring, the cloud is classified as cumulus congestus, also known as towering cumulus.