Linking Survivor Stories to Forensic Engineering: How an Interscience Approach Reveals Opportunities for Reducing Tornado Vulnerability in Residential Structures

Abstract

Abstract When a tornado strikes a permanent or mobile/manufactured home, occupants are at risk of injury and death from blunt force trauma caused by debris-loaded winds and failure of the structure. Mechanisms for these failures have been studied for the past few decades and identified common weaknesses in the structural load path. Also under study in recent decades, much has been learned about how people receive and understand warnings and determine how, when, and if they will shelter in advance. Recent research, for example, shows most people do not shelter until close to impact, after seeing, hearing, or feeling the approaching tornado. To advance beyond these innovations, a new, multidisciplinary approach was fielded in nine southeast U.S. tornadoes between 2019 and 2022. For each tornado, 1) wind engineering assessments documented near-surface wind fields, 2) structural engineering assessments documented the primary wind load path for each structure, and 3) social science interviews captured the survivor’s narrative and asked several follow-up questions to assure key items of interest were addressed in each interview. When possible, the team was multidisciplinary during the interview, enabling survivors to ask questions and better understand their experiences. Most survivors became aware of the approaching tornado with at least a few minutes of lead time, and most were able to reach a place of refuge. Most survivors recalled sensory experiences during the tornado, and about half could describe the direction or temporal sequences of damage. A case study of the Cookeville, Tennessee, tornado of 3 March 2020 illustrates the power of the integrated data assessment.