Long-Distance Debris Transport by Tornadic Thunderstorms.Part I: The 7 May 1995 Supercell Thunderstorm

Abstract

On 7 May 1995, during VORTEX 95, the Tornado Debris Project at the University of Oklahoma collected debris transported up to 190 km (120 mi) in association with an isolated tornadic thunderstorm which moved over north Texas and southern/central Oklahoma. Analysis of WSR-88D radar reflectivity data along with eyewitness accounts suggest that plumes observable in the radar reflectivity field contained debris that were transported long distances by this storm. The three main clusters of debris can be explained by at least three different modes of deposition: rear-flank deposition, left-flank deposition, and forward-flank deposition. Trajectory estimates outside the storm based on terminal fall speeds of the collected debris suggest much of the debris did not travel as far as it would if it had left the storm at upper levels in a dry state. Direct and indirect precipitation effects are diagnosed as potential factors limiting the distance transported.