Is Oklahoma's Tornado Alley shifting to the East ?

‘Tornado Alley’ may be moving to the east, according to new report published today.

The report, Spatial Trends in United States Tornado Frequency, is based on a survey of the last forty years of tornadic activity.

In that survey researchers found that whilst the incidence of tornadoes over the Midwest and Southeast have increased, the number over the central and southern plains have decreased.

“Regions in the Southeast and Midwest are closing the gap when it comes to the number of tornado reports,” said Northern Illinois University meteorologist Victor Gensini, who led the study.

“It’s not that Texas and Oklahoma do not get tornadoes,” Gensini said. “They’re still the number one location in terms of tornado frequency, but the trend in many locations is down over the past 40 years.”

Overall, about 1,200 tornadoes hit the U.S. yearly, the National Severe Storms Laboratory (NSSL) said, killing about 73 Americans each year - an average of 10 deaths per year in the Midwest (Texas, Oklahoma and Kansas) compared to some 40 deaths per year in the nine states of the Southeast.

Reasons behind these differences include that tornadoes in the Southeast tend to have longer, larger tornado paths, pass over greater concentrations of population, greater numbers of mobile homes and occur more frequently at night.

This new research is key for pinpointing future tornado damage in the U.S. "Severe thunderstorms accompanied by tornadoes, hail, and damaging winds cause an average of $5.4 billion of damage each year across the United States, and 10 billion-dollar events are no longer uncommon," the study said.

"Economic losses associated with tornadoes will continue to increase in future years," the study also warned, adding that "the combination of an increase in risk and exposure could lead to a threefold increase in tornado disaster potential."

With the eastward trend the Mid-South, an area with Memphis at its center, becomes a particular worry. It "has the greatest potential for increased tornado disasters by the end of the century," the study said.

As for what is causing this shift, the report offers no conclusions. Not that this rules out climate change. Rather, the researchers were considering the location, frequency and intensity of tornadic activity, questions provoked by “Recent trends in global and United States temperature."

Spatial Trends in United States Tornado Frequency, authors Vittorio A. Gensini and Harold E. Brooks, was published today in the journal Climate and Atmospheric Science.

(Image courtesy Northern Illinois University and USA Today)