Tornadoes account for about one in five natural hazard-related deaths in the United States. This recent study investigated the relationships between tornado casualties (injuries and deaths), storm energy, and population using the NASA SEDAC Gridded Population of the World (GPW) v4 data set. For all tornadoes, investigators found that a doubling of population increased the casualty rate by 21% while a doubling of storm energy increased the casualty rate by 33%. For the strongest storms casualty rates from increases in population and storm energy were even greater. These estimates can be used to project future changes in casualties given known population and storm trends.