Low-Level Winds in Tornadoes and Potential Catastrophic Tornado Impacts in Urban Areas

Abstract

Using an axisymmetric model of tornado structure tightly constrained by high-resolution wind field measurements collected by Doppler on Wheels (DOW) mobile radars, the potential impacts of intense tornadoes crossing densely populated urban areas are evaluated. DOW radar measurements combined with in situ low-level wind measurements permit the quantification of low-level tornadic winds that would impact structures. Axisymmetric modeled wind fields from actual and hypothetical tornadoes are simulated to impact high-density residential and commercial districts of several major cities. U.S. census block data, satellite imagery, and other sources are used to characterize and count the number of structures impacted by intense winds, up to 132 m s−1, and estimate the level and cost of resulting damage. Census data are used to estimate residential occupancy and human casualties. Results indicate that a large and intense tornado crossing through residential portions of Chicago, Illinois, could result in tragic con...