Killer Tornado Alley

Why Tennessee is a More Deadly State

By: Meteorologist Chris Justus, CBM

April 2012

For decades many southerners have grown up with a false sense of security when it comes to tornadoes. The common notion that Tornado Alley, a non-meteorological term outlining Oklahoma, Kansas, Iowa, South Dakota, Nebraska, Texas and Missouri as the only area that receives massive, devastating tornadoes is wrong. In reality, a greater percentage of stronger

twisters actually occur in the southeast. In fact, Tennessee, Alabama, Georgia, Arkansas, Mississippi and Louisiana have had significantly more fatalities than the traditional tornado alley, given a more accurate name, Killer Alley. But why would areas commonly thought as mediocre areas for severe weather be so deadly? This paper will show that meteorological factors combined with socio-economics and the publics perception of tornadoes result in the deadly results. We will examine tornado statistics from 1951-2011.

1950-2011 (52 Years)

Traditional Tornado Alley: 23,614 twisters   1,628 deaths     

KillerAlley:                         9,536 twisters    2,144 deaths

The Traditional Tornado Alley has had 14,078 or 2.5 times more tornadoes than Killer Alley. However, Killer Alley has had 516 more fatalities, 32% more deaths than The Traditional Tornado Alley.  

Comparing Major Tornadoes EF3-5

Traditional Tornado Alley: 1,226 out of 23,614 tornadoes (5%)

Killer Alley: 783 out of 9,536 tornadoes (8%)

Comparing EF4 and EF5

Traditional Tornado Alley: 256 out of 23,614 tornadoes (1%)

Killer Alley: 142 out of 9,536 tornadoes (2%)

While the Traditional Tornado Alley have the most significant tornadoes, a greater percentage of them of occur in Killer Alley.

Excluding the Unusual 2011 Season

2001-2010

Traditional Tornado Alley:  5,138 twisters      164 deaths

KillerAlley:                        2,600 twisters       247 deaths

Traditional Tornado Alley Deaths 2001-2010: (IA: 17, NE: 3, KS: 27, OK: 20, TX: 18, MO: 75, SD: 0 )

KillerAlley Deaths 2001-2010: (TN: 100, MS: 29, AL: 39, GA: 27, LA: 11, AR: 41

Top 5 Deadly States 2001-2010                 Top 5 Deadly States 1950-2011

1.     Tennessee 100 deaths                        1. Alabama 709

2.     Missouri 75 deaths                             2. Texas 555

3.     Alabama/Arkansas 39 deaths               3. Tennessee 513

4.     Indiana Florida 31 deaths                    4. Mississippi 485

5.     Georgia/Kansas 27 deaths                    5. Oklahoma 456

2001-2010 Tornadoes: OK :54  TN: 28

2001-2010 Deaths: OK: 20 TN: 100 

Tennessee By Category

1950-2011 (52 Years)

Total: 1061

EF5: 3                             EF3-EF5: 11% of all twisters

EF4: 31                           EF4: 3% of all twisters             

EF3: 87                           EF3: 8% of all twisters

EF2: 224

EF1: 434

EF0: 282

Tennessee By Decade

EF3-5                                      EF5    EF4    EF3   Total EF0-EF5

2001-2010: 23 (100 deaths)        0         4        19       284

1991-2000: 30 (36 deaths)        1          6        23       239

1981-1990: 8 (8 deaths)           0          1        7         104

1971-1980: 20 (56 deaths)        1          6        13       165

1961-1970: 12 (14 deaths)        0          2        10       85

1951-1960: 20 (77 deaths)        0          8        12       90

Why?

Population

Tennessee Tornado Deaths            Population

2001-2010: 100                       2010: 6,403,353 ( 11.5% 2000, 24% 1990)

1991-2000: 36                         2000: 5,689,283

1981-1990: 8                           1990: 4,877,185

1971-1980: 56                         1980: 4,591,120                       

1961-1970: 14                         1970: 3,923,687

1951-1960: 77                         1960: 3,567,089

                                                1950: 3,291,718

With the population in Tennessee up 1.5 million, nearly 25% since 1990 development is widespread across the state. Tornadoes that used to strike rural farm land are now devastating shopping malls, apartment complexes and housing developments. The more people in one area the great chance you have for deaths. The above chart represents the trend.

Time of Day

Night tornadoes are more common in Killer Alley, 35% of all twisters occur between 7pm and 7am. Here in Middle Tennessee that number is great, 45% of all of our tornadoes occur between7pm and 7am.

Forestry

-Forestry is more prevalent east of the Mississippi. 52% of Tennessee land is covered by forestry.

-Oklahoma only has 24% of their land covered in forestry.

-Less forestry allows for better visibility and less debris flying around.

Mobile Homes

Manufactured homes are more prevalent in the southeastern United States. In fact, in Tennessee 1 in 10 homes are mobile homes.

The problem with manufactured homes is they are bottom heavy. Often with steel foundations on the floor, when tornadoes come through they often times will flip allowing the heavy steel to crush everything inside.

Humidity

Storms in the southeast are able to tap into rich moisture from the Gulf. This means southeastern storms commonly have heavy rain associated with them. So tornadoes are often times hard to see rain-wrapped twisters, invisible until they are right on top of you.

Government Incentives: Through the Hazard Mitigation Assistance Grant Program states can apply for FEMA funding to try to mitigate future disasters called Hazard Mitigation Funding.

-Funds tied to previous disaster activity.

-FEMA will hand out certain percentage of money after each disaster for states to use how they deem fit to reduce future impacts.

-Each state then prioritizes requests for funding based on threats.

Oklahoma, Texas, Mississippi, Arkansas and Alabama are all states that use that funding as a way to reimburse families up to 75% the cost of building storm shelters. Meaning a $3,000 shelter will cost around $750 bucks.

Tennessee, does not. Currently the state doesnt accept applications for funding from individuals. Instead Mitigation Money is going into community shelters. In 2012 $250,000 dollars of TNEMA funding went to three safe rooms at Austin Peay State University in Clarksville, TN. FEMA contributed $1.5 million to the project. TNEMA

Statement from TNEMA on June 8, 2011: Tennessee: Although considered an eligible project under FEMAs Hazard Mitigation Grant Program, safe room project applications are not accepted by the State. The reason is simple: Tennessee has never received enough disaster funds to fairly disseminate the funds to all who would be interested. In order to have the greatest impact with limited funds, the state concentrates on community shelters or reinforced corridors in schools where it can provide a safe place for many people at one time.

Tennessee Hazard Mitigation Grant Program Funding 2006-2011

Disaster Declared                 Reason                         Funding

1. 4/5/2006            Storms/Tornadoes/Flooding      $721,253

2. 2/7/2008             Storms/Tornadoes/Flooding     $3,000,686       

3. 2/17/2009                   Winter Storms                  $986,455

4. 5/15/2009          Storms/Tornadoes/Flooding      $700,838         

5. 7/13/2009          Storms/Tornadoes/Flooding      $1,406,262

6. 10/21/2009         Storms/Tornadoes/Flooding      $368,166

7. 5/4/2010                 Historic May Flood              $81,558,315

8. 9/15/2010           Storms/Tornadoes/Flooding      $635,538

9. 3/31/2011          Storms/Tornadoes/Flooding      $1,157,602

10. 5/1/2011          Storms/Tornadoes/Flooding      $9,217,793

11. 5/9/2011          Storms/Tornadoes/Flooding      $1,289,735

12. 5/9/2011          Storms/Tornadoes/Flooding      $5,459,858

13. 7/20/2011         Storms/Tornadoes/Flooding      ????

14. 3/16/2012         Storms/Tornadoes/Flooding      ????

Funds Per Year From Tornado Related Disasters

2006: $721,253     2007: $0     2008: $3,000,686  2009: $2,807,938                   

2010: $635,538     2011: $17,124,988

Public vs. Private Tornado Shelters: Oklahoma officials are shutting down public shelters due to the encouragement to get the public on the roadway during storms. They found the public is more at risk versus staying at home. They have put more funding toward reimbursing the public on private in-home shelters. Those same shelters Oklahoma is shutting down Tennessee spent $46 million dollars to build more in the past 10 years. One of TEMAs latest shelters in 2012 was at Austin Pea State University in Clarksville that cost them $1.5 million. TEMA Director James Bassham told us this, "Quite frankly we feel like the better bang for your buck is having a shelter in a school or a community where you can get a number of people in there."

We took a closer look. The $46 million that TEMA spent on public shelters protect around 43,000 people. But, if TEMA would have put the money toward rebates, 23,000 private shelters could have been funded protecting nearly 138,000 people, over 3 times more.

Courtesy:

Bobby Boyd, National Weather Service Office Nashville, TN

The Storm Prediction Center

The United States Census Bureau

The United States Forest Service

Federal Emergency Management Agency