Land Surface Heterogeneity and Tornado Formation: A Comparison of Tornado Alley and Dixie Alley
- *Corresponding Author:
- Frazier AE
Oklahoma State University
Stillwater, OK, 74074, USA
Tel: (405) 744-2864
E-mail: [email protected]
Received Date: March 30, 2017; Accepted Date: April 24, 2017; Published Date: April 28, 2017
Citation: Frazier AE, Hemingway B, Brasher J (2017) Land Surface Heterogeneity and Tornado Formation: A Comparison of Tornado Alley and Dixie Alley. J Climatol Weather Forecasting 5:203. doi: 10.4172/2332-2594.1000203
Copyright: © 2017 Frazier AE, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Tornadoes are among the most destructive hazards to human life and property, and certain areas of the United States are more prone to these events. In particular, scientists use the terms “Tornado Alley” and “Dixie Alley” to refer to two general areas that experience higher incidences of tornadoes. While there is wide recognition that the two regions vary in the number, magnitude, and fatalities caused by tornadoes, more research is needed to better understand the reasons for these differences. The growing recognition that land surface heterogeneity may play a role in tornado formation provides motivation to compare the geographical characteristics of the two regions to determine whether there are significant differences in the landscape characteristics where severe storms form. To investigate the relationship between tornado formation and land surface heterogeneity in these two regions, we first delineate the spatial extent of Tornado Alley and Dixie Alley based on tornadic activity using a statistical test for the detection of significant clusters of spatial association. Next, using severe weather data for tornadoes and storms producing wind/hail (but no tornadoes), we investigate how land surface heterogeneity factors are related to tornado formation of weakly tornadic storms (EF0-EF1) and significantly tornadic storms (EF2-EF5) in each region using binary logistic regression. Lastly, we map probability surfaces for each region to show areas of greater risk. Results show that relationships between land surface heterogeneity and tornado formation vary from region to region. Elevation, slope, and distance to rivers are significant predictors of tornado formation, but the directionality of those relationships varies by region and storm severity. Urban land covers are associated with decreased tornado probability for all storm types in both regions. Spatial trends show an decreasing likelihood for EF0-EF1 from west to east in Tornado Alley but an increasing likelihood in that direction for EF2-EF5 storms.