VORTEK LLC

NASHVILLE REMAINS THE MOST

TORNADO-PRONE CITY DURING APRIL

March 31, 2009

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 by month of the top twenty tornado-prone cities, with Nashville, Tennessee remaining the most tornado-prone city for the month of April. The rankings, based on National Weather Service data from 1950 through 2007, are as follows:
 

 

RANK

 

STATE

 

ACF (%)

DISTURBED LAND

AREA (ACRES)

1

Nashville, TN

.0528

424

2

Oklahoma City, OK

.0517

416

3

Tulsa, OK

.0496

399

4

Topeka, KS

.0465

374

5

Wichita Falls, TX

.0451

363

6

Huntsville, AL

.0442

356

7

Shreveport, LA

.0389

313

8

Ann Arbor, MI

.0388

312

9

Little Rock, AR

.0369

297

10

Birmingham, AL

.0324

261

11

Cedar Rapids, IA

.0289

232

12

Grand Rapids, MI

.0246

198

13

Wichita, KS

.0206

166

14

Des Moines, IA

.0197

158

15

Mesquite, TX

.0187

150

16

South Bend, IN

.0184

148

17

Dallas, TX

.0176

142

18

Garland, TX

.0173

139

19

Lincoln, NE

.0159

128

20

Cincinnati, OH

.0139

112

 

The "ACF" (Annual Coverage Fraction) represents the average fraction of land area within a 20-mile radius of the city disturbed by tornadoes during April for the 58-year period from 1950 through 2007. The "disturbed land area" represents the average number of acres of land within a 20-mile radius of the city disturbed by tornadoes during April for the same 58-year period.

VORTEK

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Huntsville, AL 35801

256-533-9371

vortek@mindspring.com