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Severe hail is a common event in the United States and few studies have been conducted using high-resolution data to determine the spatial and temporal variability of hail occurrence. Given the coverage of Weather Surveillance Radar-88 Doppler radars (WSR-88D; Crum and Alberty 1993 ) over the Southern Plains of the United States, recent technological advancements including hail detection algorithms and powerful new geographic information systems (GIS) tools, a new methodology was developed to quantify the occurrence of severe hail. The methodology was tested using a dataset spanning 2001–2003 from 15 radar sites across eight states. The Hailswath algorithm developed at Weather Decision Technologies, Inc. was used to estimate severe and significant hail for each individual storm during the study period. Due to the discrete nature of the Hailswath algorithm output, it was manually contoured to create a coherent swath of the most likely area of severe (19 mm in diameter; 0.75 inches) and significant hail (51 mm in diameter; 2 inches). Finally, the results of these analyses were compiled monthly, annually, and for the total duration of the study period using a variety of GIS tools. A thorough demonstration of the data analysis process and results is presented, and the benefits and limitations of the method used to investigate the occurrence of severe hail are explained. [ABSTRACT FROM AUTHOR]