A REASSESSMENT OF US LIGHTNING MORTALITY

Lightning is a unique weather hazard when compared to other perils such as tornadoes, flash floods, and hurricanes since lightning itself does not constitute a criterion for a severe event according to National Weather Service guidelines. Indeed, the mitigation of lightning casualties is complex since lightning is often preceded by no formal warning and little informal warning, because of the unpredictability and random nature of a lightning strike. This investigation tallies and assesses the fatalities produced by lightning in the United States from 1959 to 2006 in order to reevaluate the specific vulnerabilities and impacts associated with this deadly hazard. The study is the first to assemble a comprehensive lightning fatality dataset for the United States using both governmental and nongovernmental data sources. As with previous studies that have examined data discrepancies at the state level, the comparisons between traditional data sources such as Storm Data and other alternative data sources reveal significant differences in fatality tallies for the years when analyses overlap. Mortality data are gridded and mapped at a much finer resolution than previous studies in order to reveal the distinctive spatial distributions of lightning fatalities, which are a combination of both risk and human vulnerability. Although lightning is not a criterion for either tornado or severe thunderstorm warnings, we assess whether lightning fatalities during the 1994-2004 period occurred in conjunction with these types of warnings. These warning data, in addition to radar analyses from 1998 to 2006, illustrate that unorganized, nonsevere thunderstorms are the most likely storm morphology yielding killer lightning events.