Supplemental Damage Indicators Discovered in Recent Strong Tornadoes
Documentation of each bulleted DI will be provided. Additionally, the track-relative locations of each DI were identified and compared to the EF-ratings of nearby standard EF-scale DIs, where possible. An estimation of minimum wind speed necessary to produce the observed degree of damage (DOD) was made, where possible, by using the weight and cross-sectional area of the DI as well as the estimated pressure coefficient as induced by the atmospheric pressure drop inside the tornado (using laboratory vortex measurements). For example, preliminary analysis of lofted parking stops offers support for the assigned EF-5 rating in the Joplin tornado. Additionally, the transmission line tower's observed DOD (collapsed and removed from original location) in the Bowdle, SD tornado exceeded the highest DOD provided in the EF-scale (collapsed tower). Recommendations for how to implement these supplemental DIs in the EF-scale will be provided.