Funnel cloud

Under a funnel cloud, also called funnel or funnel cloud abbreviation of the term, refers to the visible portion of a rotating column of air with a more or less vertical rotation axis.

It extends mostly as a cone or needle-shaped Cloudscape in the updraft of a shower or thunderstorm cell down. They are occasionally observed on rainless cumulus clouds. In supercells often occur below or close to a wall cloud ( engl. wall cloud ).

Demarcation

A funnel cloud, as distinct to a tornado, by definition, not the complete vertebrae, but only its visible portion. The vortex itself is made below the funnel cloud down continuously and therefore can at any time turn into a tornado. It is important that the continuous rotation does not have to be optically by a "cloud hose " seen to exist. So once show under a funnel cloud turbulence or damage to the soil, it is a tornado. A vortex which demonstrably has no contact with the ground, so kinks before, is called, however, as Blindtrombe.