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

Lightning and tornadoes are two life-threatening environmental hazards that can lead to casualties. Given the large number of large outdoor public gatherings (LOG) such as amusement parks, concerts, festivals, sporting events, etc. throughout the conterminous United States, a more thorough understanding of how human exposure to these deadly hazards changes over time and across geographic space is needed. This study examines potential lightning and tornado exposure to LOG event attendees and associated LOG venue attributes such as location, seasonal event timing, number of events throughout the year, maximum attendee capacity, etc. Analyses permitted the creation of LOG lightning (LOG_LT) and tornado (LOG_EF0+ and LOG_EF2+) risk indices that denote the potential lightning and tornado exposure for 477 different LOG venues and 16,232 individual LOG events. Findings reveal that amusement parks, Major League Baseball (MLB) games, and state fairs during warm season months (i.e., March through August) have the greatest potential exposure to lightning and tornadoes compared to all other LOG events. Specifically, the New Orleans Jazz and Heritage Festival in Louisiana during May ranks highest in terms of potential lightning exposure, while Coors Field in Denver (June), CO and Six Flags Over Texas in Arlington (April) encompass the greatest potential exposure to all (EF0+) and significant (EF2+) tornadoes, respectively. Based on these findings, governing bodies for LOG events and host venues should continue to develop safety measures and risk reduction strategies aimed at improving lightning and tornado safety, especially as hazard threats evolve over time and geographic space.