A dasymetric method to apportion tornado casualty counts spatially Tyler Fricker, James B. Elsner, Victor Mesev, & Thomas H. Jagger Department of Geography, Florida State University, 113 Collegiate Loop, Tallahassee, FL 32306, USA. E-mail: tfricker@fsu.edu Abstract This paper describes a dasymetric technique to spatially apportion casualty counts from tornado events in the U.S. Storm Prediction Center’s database. Apportionment is performed with respect to the proportion of damage path area and to the underlying population density. The method is illustrated with raster grids on tornadoes occurring between 1955 and 2015 within the most tornado-prone region of the United States. Validation of the results using county- and grid-level data reveals strong correlation between dasymetric es- timated and location-specific counts. On a broad spatial scale the method pro- vides a better estimate of where casualties have occurred than counting the number of casualty-producing tornadoes. Case studies using the 1974 Xenia, OH and the 1994 Piedmont, AL tornadoes highlight limitations of the method and indicate that results will be improved with more precise tornado path in- formation. Future work that includes socioeconomic variables (demographics, ethnicity, poverty and housing stock/value) might allow populations to be pro- filed with regards to vulnerability. Keywords: Dasymetric mapping, tornado, casualties 1. Introduction Tornadoes are severe wind storms capable of catastrophic physical damage and human casualties. In 2014 the National Climatic Data Center (NCDC) Preprint submitted to Journal of L A T E X Templates April 20, 2017