Thursday, December 9, 2010

Part I: 50+ Years of Hail Data

As 2010 comes to an end, I though it would be interesting to investigate the past 50+ years of the severe weather climatological record. While there are plenty examples of the problems with severe weather reports (e.g., Doswell and Burgess 1988;Grazulis 1993; Brooks and Doswell 2001; Brooks and Doswell 2002; etc.), they are the only "ground truth" data available to researchers. For part 1 of this series I will be examining hail data; however, I plan to examine tornado, wind, and all reports. It should be noted that all data presented in this series is courtesy of the Storm Prediction Center's (SPC) SVRGIS dataset.

Quick hail facts from 1955-2009
  1. 6.6% of hail all reports can be considered significant (+2" in diameter).
  2. May exhibited the highest frequency of severe reports per year at ~1,080.
  3. An average year will see 4,654 severe and 308 significant severe hail reports.

Below, you will find a potpourri of climatological maps/graphs regarding hail data. Enjoy!

(Click for animation)

Watch closely and you will be able to see urban areas and CWA boundaries...


Brooks, H. E., and C. A. Doswell III, 2001: Normalized damage from major tornadoes in the United States: 1890–1999. Wea. Forecasting, 16, 168–176.

Brooks, H. E., and C. A. Doswell III, 2002: Deaths in the 3 May 1999 Oklahoma City tornado from a historical perspective. Wea. Forecasting, 17, 354–361.

Doswell, C. A., III, and D. W. Burgess, 1988: On some issues of United States tornado climatology. Mon. Wea. Rev., 116, 495–501.

Grazulis, T. P., 1993: Significant Tornadoes: 1680–1991. Environmental Films, 1326 pp.

(EDIT 12/09/10: Added normalized county map)