Fluctuations of Lightning Casualties in the United States: 1959–1990

Abstract

Long-term fluctuations in the number of lightning deaths and injuries from 1959 to 1990 have been examined for the contiguous United States. After taking into account the population increase, there was an overall trend amounting to a 30% reduction in casualties during the period. It is possible that this trend resulted from improved forecasts and warnings, increased education efforts of the public, and socioeconomic changes. In addition, there was a 40% reduction in the number of deaths but not of nonfatal injuries. This additional reduction in deaths was probably due to improved medical attention given to lightning victims and a wider knowledge of cardiopulmonary resuscitation techniques among the public. Improved medical care would increase the chances of a person surviving a lightning strike but would not affect the total number of casualties. Superimposed on the overall downward trend there were fluctuations of one or two decades in duration. From 1959 until 1968 there was a sharp reduction in the number of casualties, but starting in 1969 and continuing until the present, there was an overall increase. These oscillations appear to be climatologically related. The patterns of these fluctuations were parallel to nationwide changes in thunder-day frequencies, cyclone frequencies, and surface temperature values, representing thunderstorm, synoptic, and continental scales.