‘Tornado alley' has been expanding over the past 50 years, new study finds

A new research paper recently submitted to the Journal of Applied Meteorology and Climatology confirms what AccuWeather reported in 2022: tornadoes have shifted east from classic "tornado alley" in the Plains to be more prevalent in parts of the South and Midwest over the last 50 years.

Tornado Frequency Trends 2022

This comes on the heels of a research paper in 2022 that concluded that large tornado outbreaks have shifted geographically, with the nucleus shifting to the Southeast during the recent 31 years compared to the earlier records. Additionally, a study conducted in 2018 and published in the journal Nature showed that the ingredients required to produce long-lived twisters were flourishing more in the Mississippi River valley in the last 20 years than in parts of the Plains.

This most recent study examined the years 1973-1996 vs.1997-2020 and found that both the number of tornadoes and the length of tornado paths increased significantly in parts of the Southeast, while they decreased in the Plains.

The starting year of 1973 was picked because that was the year that the Fujita Tornado Scale was implimented.

Expanding the study to begin in 1951 also highlighted tornado changes in different regions for different seasons. The period of March-May, which has historically been called "tornado season," showed the highest shift from the Plains to the Southeast and Midwest, between 1951-1985 and 1986-2020.

Summer showed smaller changes, with a marked reduction in tornadoes in Florida. Fall, covering September through November, had an increase in twisters in the Southeast and mid-Atlantic, while winter tornadoes increased from Louisiana to Kentucky and in the mid-Atlantic.

AccuWeather Severe Weather Expert Dan DePodwin explained, "While recent research has demonstrated a potential shift of where tornadoes are most frequent over the long term, it's important to remember each year presents a unique weather pattern that can favor tornadoes in different areas."

"In 2024," DePodwin continued, "the more traditional tornado alley (southern Plains and Midwest) has been far more active than in recent years, and there have been significantly fewer tornadoes across the Southeast this year. The bottom line is that tornadoes can occur anywhere across the U.S., and are most common across the Plains, Midwest and Southeast."

Dr. Harold Brooks, senior research scientist at the National Oceanic and Atmospheric Administration NOAA, told AccuWeather in 2022 that families and residents of the Southeast are more vulnerable to tornadoes because there is a higher level of poverty and more people who live in manufactured homes.

AccuWeather Chief Meteorologist Jonathan Porter says that it is essential to have a plan in place in case a tornado strikes -- no matter where you live.

"It's important to understand about the tornado hazard that there is a risk anywhere in the U.S., and you have to have a simple plan about what you and your family or your business will do if you're immediately threatened by a tornado," Porter said.

"Sometimes, you only have a matter of a couple of minutes to react, so I always tell people a little bit of planning goes a long way. Simply talk with your family about the safest part of your house to take shelter. If your family is not all at home when severe weather strikes, agree on a place to meet if communications are down or if your home is unreachable," Porter added.