Spatiotemporal Analyses of Lightning and Tornado Exposure to Large Outdoor Gatherings in the Conterminous United States

Abstract Lightning and tornadoes kill more than 100 people per year on average throughout the United States. This study examines potential human exposure to lightning and tornadoes for U.S. large outdoor gathering (LOG) events such as amusement parks, concerts, festivals, and sporting events. Specifically, LOG event attributes such as location, event date, number of events throughout the year, and maximum venue capacity are combined with climatological estimates of lightning and tornado activity to estimate potential worst-case LOG attendee exposure for 477 LOG venues across 16 232 individual LOG events throughout the year. Analyses permitted the creation of monthly LOG lightning (LOG LT ) and tornado (LOG EF0+ and LOG EF2+ ) risk indices that denote potential lightning and tornado exposure for the LOG events assessed in this study. The findings reveal that amusement parks, Major League Baseball (MLB) games, and state fairs during warm-season months (i.e., March–August) have the greatest potential exposure to lightning and tornadoes compared to all other LOG events. The New Orleans Jazz and Heritage Festival during May ranks the highest in terms of potential lightning exposure, while Coors Field in Denver, Colorado (June), and Six Flags Over Texas in Arlington (April) encompass the greatest potential exposure to all EF0+ and significant EF2+ tornadoes. Based on these findings, LOG venue operators and governing bodies should continue to develop risk reduction strategies aimed at improving lightning and tornado safety, especially as lightning and tornado hazard threats evolve over time and across geographic space.