Deadly storms underscore new research finding: Mid-South is most vulnerable region to tornadoes

Feb 08, 2008
Relative frequency of killer tornado events
Relative frequency of killer tornado events, 1950-2004. Click on the image for a larger and complete view. Credit: Northern Illinois University

The tornadoes that swept across the mid-South on Tuesday and Wednesday illustrate in tragic fashion the findings of a recently published study by Northern Illinois University meteorologist Walker Ashley.

Ashley found that while the “tornado alley” region of the Great Plains boasts the most frequent occurrence of tornadoes, most tornado fatalities occur in the nation’s mid-South region, which includes parts of Arkansas, Tennessee, Alabama and Mississippi.

“The country’s most vulnerable region for tornado-related fatalities and killer tornado events basically stretches from Little Rock to Memphis to Tupelo to Birmingham,” Ashley said.

He compiled and analyzed a data set of killer tornadoes dating back to 1880, examining their spatial distribution. The study was published in the December issue of the American Meteorological Society's journal, “Weather and Forecasting.”

Earlier this week, tornadoes swept across the South, killing more than 55 people in Tennessee, Arkansas, Kentucky and Alabama and injuring hundreds.

Ashley cited a number of factors that combine to make the mid-South particularly vulnerable. These factors include:

-- Mobile home density. The NIU meteorologist said 44 percent of all fatalities during tornadoes occur in mobile homes, compared to 25 percent in permanent houses. The southeast United States has the highest percentage of mobile-home stock compared with any other region east of the Continental Divide. “Mobile homes make up 30 to 40 percent of the housing stock in some counties in the deep South,” Ashley said. “By far, mobile homes are the most vulnerable structures in a tornadic situation.”

-- Nighttime tornadoes. The southeast United States has a higher likelihood of killer nighttime tornadoes. Most states within this region have greater percentages of tornado fatalities occurring at night than other states.“I just completed another study that shows tornadoes from the midnight to sunrise period are 2.5 times as likely to kill as daytime events,” Ashley said. Further, nocturnal tornadoes are more difficult to spot, and people are more likely to be asleep when warnings are issued.

-- Forested areas. Whereas regions within the Great Plains by definition are lacking in tree cover, the mid-South region is more forested, leading to reduced visibility both for the public and spotters.

-- Early season storms. Storms that occur before the national peak in the severe storm season, which spans May and June, may catch people off guard during a tornado event.
Complacency. In contrast to other parts of the country, the South lacks a focused “tornado season,” which can lead to complacency. “In the South, people think tornado alley is where you get tornadoes,” Ashley said. “That sort of perception also leads to complacency, which in turn leads to higher fatality rates.” He points out that Oklahoma is known worldwide for the frequency of its tornadoes. Yet the state has fewer fatalities than Arkansas, Alabama and Mississippi.

Source: Northern Illinois University

Explore further: Mexico's Volcano of Fire blows huge ash cloud

add to favorites email to friend print save as pdf

Related Stories

New satellite movie shows US pre-winter wintry outbreak

Nov 14, 2014

(Phys.org) —Three days of satellite imagery from NOAA's GOES-East satellite were compiled into an animation that showed the progression of the storm system that dropped snow and brought gusty winds to the ...

New poll reveals what Americans fear most

Oct 21, 2014

Chapman University has initiated the first comprehensive nationwide study on what strikes fear in Americans in the first of what is a planned annual study. According to the Chapman poll, the number one fear in America today ...

Far more displaced by disasters than conflict

Sep 17, 2014

Disasters last year displaced three times more people than violent conflicts, showing the urgent need to improve resilience for vulnerable people when fighting climate change, according to a study issued ...

Recommended for you

Erosion may trigger earthquakes

Nov 21, 2014

Researchers from laboratories at Géosciences Rennes (CNRS/Université de Rennes 1), Géosciences Montpellier (CNRS/Université de Montpellier 2) and Institut de Physique du Globe de Paris (CNRS/IPGP/Université Paris Diderot), ...

Strong undersea earthquake hits eastern Indonesia

Nov 21, 2014

A strong undersea earthquake hit off the coast of eastern Indonesia on Friday, but there were no immediate reports of injuries or serious damage and officials said it was unlikely to trigger a tsunami.

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

zevkirsh
not rated yet Feb 08, 2008
tornadic situation ...awesome , didn't even know tornadic was a word.
aufever
not rated yet Feb 08, 2008
Lots more basements in Oklahoma than the rest of the belt. Most mobile homes don't have a storm cellar, which can be built for less that $10K, which is cheap insurance.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.