Advancing Forensic Engineering Analyses of Tornadoes with Survivor’s First-Hand Accounts

Abstract

When a tornado strikes a permanent or mobile/manufactured home, the people inside are at risk of injury and death from blunt force trauma caused by debris-loaded winds and failure of the structure. Although the mechanisms for these structural failures have been studied in recent decades, linking how tornadic winds interact with residential buildings and how human decisions affect survival has rarely been done due to the inherent complexity and cost of conducting joint social science, forensic engineering, and wind engineering assessments. This study developed and tested an interscience protocol to holistically evaluate risk factors related to the tornado and surroundings, efficacy of available shelter, and influences on decision-making regarding sheltering in individual homes in the southeast U.S. Interviews with tornado survivors at over 90 home sites ranged from 8 to 90 min long. We developed our protocol through the course of the study, ending with one page of phrases to prompt the interviewer, who could the retain eye contact and build relationship with the survivor through the course of the interview. The final protocol also included a method for noting whether topics had been raised in the survivor’s story and had also been asked in a follow-up question. Five tornado deployments were particularly successful, with nine to 18 interviews for each of those tornadoes. These tornadoes occurred at different times of day and days of the week. This talk will focus on how key factors in survivor’s stories varied across the events and when the factors did not have the intended effect; for example, some knew about the chance of tornadoes but were not monitoring the weather. Patterns emerged for most tornadoes, with environmental cues (e.g., seeing, hearing, or feeling the tornado coming) being the most important factor in sheltering decisions. Alerts were particularly important for the two nighttime tornadoes. The talk will close with a few highlights from the interscience analysis, illustrating how survivors’ stories, photo/videos, and access to structural elements were crucial for understanding how the tornado interacted with the residence.