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Where Tornadoes Strike Most Frequently Is Changing | The Weather Channel
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Tornado Safety and Preparedness

Where Tornadoes Strike Most Frequently Is Changing

On April 12-13, 2020, over 140 tornadoes touched down from Texas to Maryland.

Meteorologists considered it to be one of the biggest tornado outbreaks in modern history. The outbreak skewed Southeast, with a number of longer-track tornadoes hitting Mississippi, Tennessee and South Carolina.

NIXVILLE, SC - APRIL 13: Two men talk in front of a home destroyed by a tornado on April 13, 2020 near Nixville, South Carolina. A string of storms across the southern United States that began Easter Sunday and continued into today produced multiple tornados resulting in more than 30 deaths and dozens more injuries.  (Photo by Sean Rayford/Getty Images)
NIXVILLE, SC - APRIL 13: Two men talk in front of a home destroyed by a tornado on April 13, 2020 near Nixville, South Carolina. A string of storms across the southern United States that began Easter Sunday and continued into today produced multiple tornados resulting in more than 30 deaths and dozens more injuries.
(Getty Images/Sean Rayford / Stringer)

The states impacted in the 30 largest tornado outbreaks from 1950-2019 were almost all east of the Mississippi River.

A study published in 2018 suggests tornadoes appear to have increased since the late 1970s in parts of the Midwest and Southeast.

image
Changes in tornado frequency from 1979-2018 where warm colors indicate increases in tornado frequency and cool colors indicate decreases in tornado frequency.
(Victor Gensini, Department of Geographic and Atmospheric Sciences, Northern Illinois University)

Meteorologists have some theories as to why this appears to be happening which include climate change and natural variability. It's proven difficult to land on an exact cause for a number of reasons, including more erratic tornado activity and the broad impacts of climate change.

For example, according to a 2021 study published in Bulletin of the American Meteorological Society (BAMS), climate change may be making summers in the South less favorable for thunderstorms that spawn tornadoes, but winters more favorable for them.

"Because of this, it will probably take much longer for scientists to detect with confidence any biases in tornadoes from climate change alone, rather than typical year-to-year variability," said Jonathan Erdman, Senior Meteorologist at weather.com

The Tornado Alley Problem

Extreme weather on the high plains of Nebraska with this stunning rotating supercell mesocyclone, Nebraska, USA
(Getty Images/John Finney Photography)

Many people assume the strip of Plains states that have long been considered part of the so-called Tornado Alley see the most tornado activity, but that is largely a misconception.

"If you examine tornado tracks since 1950, it's hard to find any single alley," said Erdman. "Tornadoes are most frequent in the Plains, Midwest and Southeast into Florida, but that seems to be too broad an area for use of the term 'alley'." As such, meteorologists like Erdman don't typically rely on the term anymore.

MORE: (Safest Places to Wait Out a Tornado)

So rather than a shift, the uptick in tornado activity in states South and Southeast of the Mississippi River like Alabama, Arkansas, Missouri, Tennessee and Kentucky is more likely an expansion of the higher risk area.

Meanwhile, in Texas, Oklahoma and other Plains states long-considered part of Tornado Alley, there have been fewer tornadoes since the late 1970s, which may be attributed to drier weather overall in the Plains. These states and others that make up the infamous corridor still typically wrack up the most tornadoes annually though.

Tornadoes Are Different in the South

NASHVILLE, TN - MARCH 03:  A television news crew works in front of a mural on heavily damaged The Basement East in the East Nashville neighborhood as lightning strikes in the background on March 3, 2020 in Nashville, Tennessee. A tornado passed through Nashville just after midnight leaving a wake of damage in its path including two people killed in East Nashville. (Photo by Brett Carlsen/Getty Images)
NASHVILLE, TN - MARCH 03: A television news crew works in front of a mural on heavily damaged The Basement East in the East Nashville neighborhood as lightning strikes in the background on March 3, 2020 in Nashville, Tennessee. A tornado passed through Nashville just after midnight leaving a wake of damage in its path including two people killed in East Nashville.
(Getty Images/Brett Carlsen / Stringer)

Part of what makes tornadoes different in the South and Southeast is the terrain. According to a study recently published in BAMS, tornado impacts in the Southeast U.S. can be more devastating as a result of "larger damage footprints intersecting more vulnerable populations (e.g. poverty and manufactured homes)."

So it's not simply that the South and Southeast are more densely populated; there is a higher number of less sturdy homes, which makes the areas more prone to damage from a tornado.

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South and Southeast states have more tree coverage than the classic Plains Tornado Alley states, which plays a part, too.

"Tornadoes don't simply damage buildings, they also knock down trees, sometimes onto homes and vehicles," said Erdman. "This makes the more tree-covered Southeast more vulnerable to severe storms than, say, the High Plains."

More trees and hillier terrain can also make it harder to spot a tornado than in the flatter, less tree-covered Plains, noted Erdman. What's more, because the South and Southeast are closer to the Gulf of Mexico, tornadoes are often accompanied by more rain, which can mask them.

And while many tornadoes that occur in the South and Southeast happen during the typical peak tornado season of spring, winter tornadoes are more common in the Southeast than in the Plains, where cold air tends to dominate.

How Southerners Can Be Prepared

JOPLIN, MO - MAY 19: Camryn Dean,7, plays in the newly built tornado shelter behind her mother's rebuilt home in the heart of what was once nothing but debris and destroyed homes after a tornado hit the neighborhood almost one year ago on May 19, 2012 in Joplin, Missouri. Tuesday will mark the one-year anniversary of the EF-5 tornado that devastated the town. The tornado left behind a path of destruction along with 161 deaths and hundreds of injuries, but one year later there are signs that the town is beginning to recover.
(Getty Images/Joe Raedle / Staff)

Mobile and manufactured homes are the most susceptible to tornado damage.

If you live in such a home in the South or Southeast, the best way to protect yourself and your family is to have a safe room constructed on your property. However, since that can be cost prohibitive for some, another option is to find your nearest local shelter and make sure you can get there quickly when a warning is issued.

Otherwise, find out where the safest place in your home is ahead of time. It's usually in the basement or in an interior room on the lowest floor, like a closet or bathroom.

Erdman also advises having multiple ways to receive severe weather alerts from the National Weather Service. If you have alerts set up on your smartphone and there's a threat of severe weather overnight, make sure your 'Do Not Disturb' feature is turned off and the volume is turned up loud enough to wake you. Don't depend on outdoor sirens to wake you. They're designed to warn people outside. Unless you live right next to it, your local tornado siren may not be loud enough to do the job.

(MORE: Your Smartphone Can Keep You Safe in Severe Weather. Here's What You Need to Do)

Finally, don't wait to take action when you receive an alert to seek shelter. A tornado is likely mere minutes away, so every second counts.

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