ENGINEERING ANALYSIS INC.

PROBABILITY OF TORNADIC OCCURRENCE IN THE TWENTY MOST TORNADO-PRONE U.S. CITIES DURING JULY

June 25, 1999 PRESS RELEASE

As part of an ongoing company-funded research study of tornadic risk assessment, by means of the Site Assessment of Tornado Threat (SATT) software, Engineering Analysis Inc. (EAI) has determined the rankings of the top twenty tornado-prone cities with populations in excess of 100,000 for the month of July. The rankings, based on National Weather Service data from 1950 through 1997, are as follows: 

                                                Disturbed Land
Rank      State         Probability Fraction      Area (Acres)          
  1     Minneapolis, MN            1.84 · 10-04          148
  2     St. Paul MN                1.59 · 10-04          128
  3     Lansing, MI                2.93 · 10-05           24
  4     Naperville, IL             2.26 · 10-05           18
  5     Cedar Rapids, IA           2.18 · 10-05           18  
  6     Aurora, IL                 1.87 · 10-05           15
  7     Lincoln, NE                1.83 · 10-05           15
  8     Lexington, KY              1.65 · 10-05           13
  9     Springfield, IL            1.55 · 10-05           12
 10     Indianapolis, IN           1.53 · 10-05           12
 11     Ann Arbor, MI              1.45 · 10-05           12
 12     Madison, WI                1.36 · 10-05           11
 13     Overland Park, KS          1.02 · 10-05            8
 14     Sioux Falls, SD            7.69 · 10-06            6
 15     Tampa, FL                  7.46 · 10-06            6
 16     Cincinnati, OH             5.43 · 10-06            4
 17     Huntsville, AL             5.20 · 10-06            4
 18     Nashville, TN              4.84 · 10-06            4
 19     South Bend, IN             3.49 · 10-06            3
 20     Houston, TX                3.27 · 10-06            3

The "probability fraction" represents the average fraction of land area within a 20-mile radius of the city disturbed by tornadoes during July for the 48-year period from 1950 through 1997. The "disturbed land area" represents the average number of acres of land within a 20-mile radius of the city disturbed by tornadoes during July for the same 48-year period.

Welcome Page || Background Information || Software || Customers || Contents || Outside Links || Feedback