Science Daily December 21, 2018
Researchers at Ohio University demonstrated that tornadoes form at the ground and move up rapidly, contrary to the long-held hypothesis that most tornadoes form at cloud level and descend to touch the earth. They coupled visual and near-surface radar observations from the El Reno 2013 case enabled them to analyze the tornadogenesis process. The findings indicate that a tornado-strength vortex can be active on the ground for a minute or more before the deeper tornadic column forms and is picked up by conventional radar. However, tornado warnings are issued based on radar readings that pick-up vortex signatures at or above cloud level. The challenge is in getting those kinds of readings quickly. Conventional radar can’t get ground-level readings over a broad area because objects in the way… read more.
Example evolution of tornado-strength rotation with time and height. Credit: Jana Houser/Ohio University.