Wall cloud
Videos
A wall cloud is a large, localized, persistent, and often abrupt lowering of cloud that develops beneath the surrounding base of a cumulonimbus cloud and from which tornadoes sometimes form. It is typ
A rain-free base with a wall cloud lowering in the foreground and precipitation in the background. Taken in Needmore, Texas.
A wall cloud with tail cloud.
A shelf cloud over Enschede, Netherlands
A tornadic wall cloud with RFD clear slot.
Tornadogenesis
Videos
Tornadogenesis is the process by which a tornado forms. There are many types of tornadoes, varying in methods of formation. Despite ongoing scientific study and high-profile research projects such as
A sequence of images showing the birth of a supercellular tornado. First, the rain-free cloud base lowers as a rotating wall cloud. This lowering concentrates into a funnel cloud, which continues descending simultaneously as a circulation builds near the surface, kicking up dust and other debris. Finally, the visible funnel extends to the ground, and the tornado begins causing major damage.
Tornadogenesis occurring in Falcon, Colorado. Note the faint dust swirl beneath the funnel cloud.