WeatherKansas City Spring Weather Special


Tornado Alley, Dixie Alley: Last 2 severe weather seasons compared to 20-year average

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Posted at 10:45 AM, Mar 30, 2022
and last updated 2022-03-30 20:05:34-04

KANSAS CITY, Mo. — The United States has more tornadoes than any other country in the world.

On average, the U.S. sees about 1,200 tornadoes in a year, with the second most found in Canada with only 100 tornadoes.

Tornadoes can happen anytime, anywhere, but they’re more likely to form east of the Rocky Mountains.

The traditional Tornado Alley includes Plains states from Texas to Nebraska, but there’s another area in the southeast that experiences its fair share of powerful tornadoes. Meteorologists consider this hot spot Dixie Alley.

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These regions are in a prime location for tornadoes due to the influence of the Rocky Mountains, the desert southwest and moisture from the Gulf of Mexico.

Breaking it down, the Rocky Mountains run mostly north to south, allowing the cold dry air from Canada to work its way southward and the warm, moist air over the Gulf of Mexico to move northward.

The other factor is the hot, dry air from the desert southwest. This moves over the mountains and influences the middle part of the atmosphere.

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This difference in moisture content, temperature and wind speed/direction (or wind shear) will spawn the perfect setup for rotating thunderstorms and, therefore, tornadoes.

The last two severe weather seasons have been quiet in producing tornadoes over Tornado Alley.

In fact, each state within Tornado Alley saw fewer tornadoes in the last two seasons compared to the 20-year seasonal average.

"2020 and 2021 were both pretty inactive, especially in Kansas. We only had 17 tornadoes in 2020 and 37 in 2021. Our average is about 85-90," said Jenni Pittman, science and operations officer of the National Weather Service in Topeka.

Dixie Alley, on the other hand, has reported an increase.

Each state experienced more tornadoes in the last two seasons compared to their 20-year average.

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Pittman believes La Nina — described by the NWS as the periodic cooling of ocean surface temperatures in the central and east-central equatorial Pacific — to be the cause.

“In the last couple of years, I think La Nina has a big influence," Pittman said. "We've had La Nina both last winter and this winter as well. That tends to bring an earlier and more intense severe weather season to the southeast U.S."

She also says that it’s not so much about a shift of Tornado Alley but rather an expansion to include areas that haven’t seen as much activity in the past.

The best defense against severe weather is practice and preparation, no matter whether in Tornado Alley or Dixie Alley.