The Tornado Archive: Compiling and Visualizing a Worldwide, Digitized Tornado Database

Abstract Given inconsistencies in reporting methods and general lack of documentation, the creation of a unified tornado database across the world has been an elusive target for severe weather climatology purposes and historical interest. Previous online tornado documentation has also often been inconsistent or is now defunct. Many individual countries or continents maintain tornado information through either government-sponsored or independent organizations. The Tornado Archive was developed to create a first-of-its-kind digitized synthesis of worldwide tornado documentation, using the most complete sources of information available for regions known to be tornadically active. Spatial and temporal trends in tornado occurrence and reporting can be visualized through an interactive user interface with a variety of filtering methods and environmental reanalysis datasets, such as the fifth major global reanalysis produced by ECMWF (ERA5). The additional data introduced using Thomas Grazulis’ Significant Tornadoes may be beneficial for tornado climatology studies over the United States. The Tornado Archive is also intended to be a collaborative exercise, with clear data attribution and open avenues for augmentation, and the creation of a common data model to store the tornado information will assist in maintaining and updating the database. In this work, we document the methods necessary for creating the Tornado Archive database, provide broader climatological analysis of spatiotemporal patterns in tornado occurrence, and outline potential use cases for the data. We also highlight its key limitations and emphasize the need for further international standardization of tornado documentation.