Tornado alley moving eastward

Over the past four decades, researchers have discovered that tornadoes have increased over much of the Midwest and Southeast, including what has been called "Dixie Alley".

At the same time, they declined in the central and southern plains, a region traditionally known as Tornado Alley, which includes Oklahoma and Texas.

"The Southeast and Midwest regions are reducing the gap in the number of tornadoes," said Northern Illinois University meteorologist Victor Gensini, who led the team. study.

Although Tornado Alley remains the main region of tornadoes in the United States, data from 1979 to 2017 are catching up, including the Mississippi, Alabama, Arkansas, Missouri, and Illinois regions. from Indiana, Tennessee and Kentucky.

"It's not that Texas and Oklahoma do not get tornadoes," Gensini said. "They remain the first site in terms of tornado frequency, but the trend is down in many places over the past 40 years."

This new research is the key to identifying future damage caused by the tornado in the United States. "Severe thunderstorms accompanied by tornadoes, hail and high winds cause an average damage of $ 5.4 billion each year in the United States and events worth $ 10 billion are no longer rare" said the study.

"The economic losses associated with tornadoes will continue to increase in the coming years," also warned the study, adding that "the combination of increased risk and increased exposure could result in tripling the potential of tornadoes in the event of a disaster ".

In total, about 1,200 tornadoes strike the United States each year, said the National Laboratory of Violent Storms (NSSL). Harold Brooks, researcher and tornado expert, co-authored this study.

Tornadoes in the southeast also tend to be more deadly than those in the lowlands, due to several factors such as longer and wider tornado paths, an expanding population, more moblie houses, and more. more nocturnal tornadoes.

On average, about 40 people die each year in the nine states of the southeastern United States. Alabama records the highest number of deaths each year with an average of 14, according to data from the Storm Prediction Center.

The frequency of tornadoes increases in states like Arkansas, Tennessee and Mississippi, but decreases in Texas. (Photo: Adapted by Northern Illinois University from npj Climate and Atmospheric Science, Genseni / Brooks 2018)

The Mid-South, a region with Memphis in its center, is of particular concern because it "presents the greatest potential for increasing the number of tornado-related disasters by the end of the century." ", said the study.

On average, 10 people die each year from tornadoes in Texas, Oklahoma and Kansas, three states that make up the bulk of Tornado Alley. Based on data collected between 1985 and 2014, approximately 73 Americans are killed each year in the country.

Researchers in the study also do not know whether this tornado-to-east shift may be due to a natural or man-made climate change.

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