VORTEK LLC

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

August 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 August. The rankings, based on National Weather Service data from 1950 through 2005, are as follows:
 

 

 

 

Disturbed Land

Rank

State

ACF (%)

Area (Acres) 

1

Rhode Island

0.00010158

68.26

2

Wisconsin

0.00004238

1475.50

3

Minnesota

0.00002830

1439.90

4

Connecticut

0.00001507

46.97

5

Massachusetts

0.00001437

72.01

6

Nebraska

0.00001376

674.57

7

Illinois

0.00001249

444.44

8

Kansas

0.00000919

481.11

9

Iowa

0.00000886

317.54

10

Michigan

0.00000883

322.12

11

Ohio

0.00000875

229.60

12

New Jersey

0.00000822

39.25

13

Indiana

0.00000779

178.98

14

South Carolina

0.00000773

149.41

15

New York

0.00000754

228.73

16

Virginia

0.00000722

182.52

17

South Dakota

0.00000527

256.33

18

Oklahoma

0.00000492

216.32

19

New Hampshire

0.00000446

25.66

20

North Dakota

0.00000369

163.66

 

 

The Annual Coverage Fraction "ACF" represents the average fraction of land area within the boundaries of the state disturbed by tornadoes during August 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 August for the same 56-year period.