Map of All Known North American Killer Tornadoes, 1700-1999

This map illustrates the geographical distribution of all known and documented killer tornadoes in North America over the last three centuries (1700-1999), including data for Canadian, Mexican, and Cuban tornadoes. Here, we give equal attention and weight to all killer tornadoes whether they resulted in only one death, or caused hundreds of deaths. A dot for each killer tornado is plotted in the location of the place where the majority of the fatalities occurred. In cases where fatalities are equally-spread along the tornado path, the 'centroid ' location is plotted. Data is exclusively from Significant Tornadoes, 1680-1991 (Grazulis, 1993), or subsequent updates and archives. This map presents a unique perspective and differs from previous tornado fatality maps by ignoring political boundaries as well as fatality per population, or fatality per area schemes, which tend to be skewed by single high death toll tornado events. While this map is not intended as a measure of risk, it may provide an additional historical perspective on the distribution of tornado fatalities and population bias, particularly with regard to rural areas where high fatality tornadoes are less likely to encounter human targets. Brief discussion of possible interpretations of this map versus other presentations of tornado climatology and risk will accompany the map(s).