Reassessment of Lightning Mortality in the U.S.: Analyses of Contrasting Datasets, Spatial Distributions, and Storm Morphologies

Lightning is a unique weather hazard when compared to other perils like tornadoes and hurricanes since lightning itself does not constitute a criterion for a “severe” event according to NWS guidelines. Indeed, the mitigation of lightning casualties is complex since lightning is often preceded by no formal NWS warning and little informal warning (due to the rapidity of a lightning stroke). A number of studies have examined the fatality tallies of lightning events in the U.S. However, these prior investigations have two primary shortcomings: 1) they often rely upon a single, incomplete dataset – Storm Data – to derive fatality tallies, and 2) their spatial analyses of fatalities are often restricted to the national and/or state-level. Our study is the first to assemble a comprehensive lightning fatality dataset for the U.S. using a multitude of government and private enterprise data. In employing a variety of datasets, we are able to develop a more complete picture of the risks and vulnerabilities due to lightning hazards in the U.S., as well as reveal further the deficiencies of Storm Data. Moreover, in utilizing a GIS, we are able to create a more detailed analysis of the spatial distribution of lightning fatalities across the U.S. Our comprehensive spatial analyses of lightning deaths from 1959-2006 reveal fatality “hot spots”, which are centered in areas of Florida and the Gulf Coast, New England, and the Front Range. Finally, by incorporating a variety of meteorological data, we determined that unorganized, non-severe thunderstorms are the most likely storm morphology yielding killer lightning events. Knowledge of these unique patterns in the spatial distribution of lightning fatalities and the identification of thunderstorm morphology associated with lightning deaths will enhance our understanding of the risks and vulnerabilities posed by this deadly atmospheric hazard.