Altocumulus floccus
Altocumulus floccus is a cloud type named for its tuft-like, wooly appearance. The base of the cloud can form as low as , or as high as . They often form in clusters, or patches, and bases can vary in height with differing atmospheric conditions within the PBL. They are similar to Altocumulus castellanus, but often have a shallower vertical extent in comparison. Floccus clouds form when in the presence of conditional, often shallow, mid-level instability. On some occasions, such as the presence of a deeper unstable layer, these clouds can grow large enough to develop into thunderstorms. References 

Cumulus
Gliding technology