suction vortex

A suction vortex is a small, rapidly spinning vortex that can form within the larger rotating column of air in a tornado, particularly in violent tornadoes. These vortices are most evident in the "corner region" where the wind entering the base of the tornado abruptly shifts from horizontal to vertical flow. While multiple-vortex tornadoes involve several large vortices rotating around a central eye, suction vortices are much smaller and typically only extend a few hundred meters high. They are distinguished from the larger multiple vortices by their size and height. The fastest surface winds known are found around the tips of these secondary vortices. Tornadoes themselves form from strong thunderstorms, which require specific atmospheric conditions like moist, unstable air near the surface and cooler, drier air above. Rotation within the storm, known as a mesocyclone, is concentrated into a swirling column of air that can develop into a tornado.12