The Simulated Supertornado
Leigh Orf’s detailed storm simulations allowed him, Cathy Finley, and Bruce Lee to spot a never-before-seen feature of a tornado: a helix-shaped tube of air racing around the central funnel. They’ve dubbed it the streamwise vorticity current, and it could be a breakthrough in understanding how the world’s worst twisters work. —Chelsea Leu
Courtesy of Leigh Orf01The vortex: This thick column of orange stuff is a bunch of swirling air that forms the vortex of the tornado.
Courtesy of Leigh Orf02Cold pool: A region of cold air beneath the storm, formed by evaporating rain, that feeds the streamwise vorticity current.
Courtesy of Leigh Orf03Streamwise vorticity current: This spiraling river of air flows upward from the tornado’s forward flank into the core of the storm’s updraft, and the researchers believe that the low pressure helps sustain and drive the tornado.
Courtesy of Leigh Orf04Anticyclonic vortices: The chaotic air around of the tornado a tornado is filled with many smaller vortices, some of which eventually get absorbed into the growing funnel. In Orf’s simulation, these are color-coded by the direction the air is rotating—blue indicates that the air is spinning clockwise; red, counterclockwise.
