Tuba

Definition

A supplementary cloud feature consisting of a column of cloud hanging from the base of a cumulonimbus or cumulus congestus, looking like a funnel or a cone with the narrow end downward. A tuba that reaches the surface becomes a tornado or a waterspout.

Field note

Tuba is the feature to treat with the most caution. A funnel that is not yet touching the surface can descend within a minute, and the cloud base above it may be rotating. This is a shelter-now observation, not a photographic one.

Related terms

• Cumulonimbus · Cumulonimbus
• Incus · incus
• Virga · virga