Volutus

Definition

A cloud species consisting of a long, horizontal, tube-shaped roll cloud that appears to rotate slowly about a horizontal axis. It was added to the International Cloud Atlas in 2017 and applies to altocumulus and stratocumulus.

Field note

Volutus is the roll cloud of the arcus family when it is fully detached from any parent cloud. Unlike a shelf cloud it does not necessarily mean a gust front is about to hit you, but a strong second gust often follows.

Related terms

• Lenticularis · lenticularis
• Stratocumulus · Stratocumulus
• Undulatus · undulatus