Uncovering Pennsylvania’s Extended Tornado Climatology

Pennsylvania averages 17 tornadoes per year (1993-2022). Official records for tornadoes began in 1950. However, many tornadoes occurred before then, including the deadliest tornado to affect the state, an F4 in 1944 that killed 26 people across Washington, Fayette, and Greene Counties. Before 1950, data existed in many different publications but had never been combined into one unified database. This study documents a total of 1207 tornadoes between August 23, 1724, and April 1, 2023. A criterion was established from source data to help determine tornadic activity and uncover previously unlisted tornadoes. Newspaper reports were vital to help document these unlisted tornadoes and help accurately plot the paths of existing confirmed tornadoes. Hotspot and heat map analyses were created to highlight the areas with the greatest concentration of tornadoes. The results show that southwestern and southeastern Pennsylvania has the most concentration of tornadoes, possibly due to population biases.