Abstract:

Mobile, polarimetric radar data of tornadoes have increased our understanding of debris swaths and lofted debris. Recent numerical simulations have suggested that cycloidal damage swaths can result when debris is deposited as the low-level inflow turns upward in the corner region of the updraft annulus of the tornado core. Observational evidence supporting this finding is presented which suggests a major modification to the schematic model proposed by Fujita that secondary vortices create these swaths marks.

Lofted debris is analyzed using polarimetric data and by tracking debris using photogrammetric techniques on a high-resolution movie. Horizontal velocities of the lofted debris tracks are compared with radar velocities for the first time.