VORTEK LLC

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

June 27, 2007

As part of an ongoing company-funded research study of tornadic risk assessment, by means of the Site Assessment of Tornado Threat (SATT) software, VorTek has determined the rankings of the top twenty tornado-prone states for the month of July. The rankings, based on National Weather Service data from 1950 through 2005, are as follows:
 

 

 

 

Disturbed Land

Rank

State

ACF (%)

Area (Acres) 

1

Maryland

0.00353

222

2

Nebraska

0.00298

1463

3

Illinois

0.00280

996

4

Wisconsin

0.00235

820

5

Iowa

0.00225

807

6

Minnesota

0.00175

890

7

Ohio

0.00165

432

8

New Jersey

0.00162

78

9

Michigan

0.00155

564

10

Massachusetts

0.00149

75

11

New York

0.00136

414

12

Kansas

0.00129

677

13

Connecticut

0.00124

38

14

Pennsylvania

0.00124

355

15

North Dakota

0.00114

508

16

South Dakota

0.00113

551

17

Vermont

0.00093

56

18

Wyoming

0.00085

525

19

Indiana

0.00077

177

20

Kentucky

0.00060

153

 

 

The Annual Coverage Fraction "ACF" represents the average fraction of land area within the boundaries of the state disturbed by tornadoes during July for the 56-year period from 1950 through 2005. The "disturbed land area" represents the average number of acres of land within the boundaries of the state disturbed by tornadoes during July for the same 56-year period.