Spring and the Mississippi River Valley tornado have made meteorologists change their thinking from winter storms to tornadoes. It has also made many Americans question if twisters are starting to increase beyond the traditional “Tornado Alley”.
Is Tornado Alley shifting? Or were the vulnerabilities of other states just being ignored?
Let’s take a deep dive into the details and see just what experts are saying about the topic. We will look at how Tornado Alley is shifting and what’s causing it to do so.
What is Tornado Alley?
Tornado Alley is a term for the most wind and tornado-prone area in the central United States. The severe weather season that part of the country experiences a trend of destructive tornado activity, from South Dakota to north-central Texas.
The area also includes Oklahoma, Missouri, Iowa, Nebraska, Louisiana, and Eastern Colorado. This region is inclined to tornadoes because of contrasting air masses that result in severe storms.
Cold, dry air mixes with warm, moist air to produce instability in the atmosphere. It then turns into storms and, later on, a tornado. The cold, dry air comes from the Mexican Plateau, while the warm, moist air comes from the Gulf of Mexico.
The rapid circulation leads to a counterclockwise flow in the east of the Rockies. This phenomenon sets the stage for the destructive funnel.
Mejor Ernest J. Fawbush and Captain Robert C. Miller, meteorologists from the US Air Force, first used Tornado Alley. Seventy years ago, they examined extreme weather events in Texas in a study entitled Tornado Alley.
Violent tornadoes in the Tornado Alley usually occur between April and June. However, the cold and warm air mixture starts from late February to March.
Can Tornadoes Happen Anywhere in the US?
Yes. All parts of the United States are vulnerable to destructive storms and tornado damage, especially in the east of the Rockies. That’s why many meteorologists and other scientists refuse to accept the term, Tornado Alley.
The Tornado Alley only covers a part of the area that experiences deadly tornado outbreaks every year. Various studies have concluded that the Deep South encounters a similar frequency of tornadoes. Therefore, it ignores other dangerous twisters occuring in the US.
Victor Gensini, an atmospheric science professor at Northern Illinois University, thinks Tornado Alley does a “disservice” to many people.
He adds that there is no actual discontinuity if one observes the spatial risk of tornadoes.
The desire to shift away from the term also stems from the media’s focus on tornadoes in plains. Photographers take pictures of twisters in this area to show the high-contrast funnel posing on vacant farmlands.
The disaster-causing tornadoes in the South do not get the same amount of publicity. That’s because they are hidden in low clouds and wrapped in rain, almost invisible.
Is Tornado Alley Shifting East?
Experts have different answers on climate shift and whether Tornado Alley is shifting east or not. A study published in 2018 shows that the Tornado Alley may be moving.
The results indicate that tornado frequency in the Tornado Alley has been decreasing for 40 years now. Meanwhile, strong tornadoes are increasing in the Deep South and Great Lakes.
Nashville City and downtown Memphis are now more at risk of tornado activity than downtown Dallas. There was news in March 2020 about the Nashville twister, while Memphis did not experience any storm or tornado damage.
Meteorologists call this new area of frequent tornadoes the Dixie Alley. Experts acknowledge the new location of the weather pattern but state that Tornado Alley still experiences more tornadoes.
But the increasing frequency in Dixie Alley is still an essential topic for climatological research. Although it encounters fewer tornadic activities, the number of severe weather conditions and destructive tornadoes are close to Tornado Alley’s.
Ranny Vandewege, a storm chaser and Vice President of Weather Operations at DTN, thinks the Tornado Alley isn’t necessarily shifting. Instead, it’s encompassing a bigger location from Texas to Nebraska.
He backs this by pointing out the largest tornado outbreaks in 2011 and 1974, which occurred east of the Mississippi River.
Climate Change as the Culprit
The eastward shift of Tornado Alley to Dixie Alley can be traced to urbanization. Cities have widened and made fewer open spaces, causing the landscape to be more susceptible to tornadoes.
However, it’s difficult to blame urban expansion alone on this significant change. Nationwide coverage of Doppler radar also tells us that there is no single cause to this event.
Another contributing factor may be climate change. Hurricanes, tornadoes, and droughts are more common and severe because of climate change. This idea is general knowledge, as climate models have been predicting this for years.
Climate change may have shifted the jet stream and wavered the polar vortex, giving shallow dips in the jet stream over the US. A southerly dip can produce a shift to the southeast and increase the weather events in this area.
It can also change the jet stream’s power. A weaker jet stream implies tighter temperatures and pressure changes, producing more powerful thunderstorms and tornadoes.
Other possible causes may be bigger cycles in the surface temperatures of the Pacific. This variable may affect Tornado Alley, but there is insufficient data to observe the cycle.
Different Consequences Between Tornado Alley and Dixie Alley
Tornadoes in Dixie Alley may have more severe consequences than in Tornado Alley. First, the numerous trees and hills in the southeast make tornadoes less visible, especially at night. And nighttime twisters are more prevalent because of fronts’ slow progression.
The population density is also higher, making fatality rates likely higher. Warning systems are necessary for these places, especially in mobile homes. Families in mobile homes are more vulnerable because of their location and weak structures.
Dixie Alley’s Impact on Industries
The eastward shift of tornadoes puts many businesses at risk since these are home to different manufacturing facilities. Last December 14, 2021, over 70 deaths were confirmed after the occurrence of severe weather events and tornadoes in Kentucky.
It also affected seven other states and killed 12 more people. The most significant casualties were the Amazon distribution Center in Illinois and a candle factory in Kentucky.
These vast structures significantly affect local economies, which means the shift eastwards may influence fluctuations in economic activity. According to an initial estimate for damage and economic loss, storms may account for at least $18 billion.
The damage from tornadoes and fierce storms can disproportionately affect several workers in the industry.
It’s high time businesses start creating tornado-friendly conditions in the workplace to avoid fatalities.
It’s also worth noting that $30 billion of the $135 billion loss in November is all because of severe weather. These include tornadoes, destructive winds, and deadly storms.
More Dangerous Tornadoes in the South
The core of Tornado Alley implies the emphasis on plain tornadoes in Central America. Media’s focus on using high-contrast images also dismisses the Southern part of the States’ vulnerability to twisters.
Despite this, the Deep South experiences longer and more severe weather seasons. The tornadic storms are also known as high precipitation or HP supercells. These are catastrophic tornadoes.
Compared to Tornado Alley’s LP supercells, the increase in precipitation wraps the twister in the rain and makes it invisible. Even storm spotters and chasers rarely see a twister coming. You won’t also see clear videos of tornadoes in this location.
Both Tornado Alley and Dixie Alley experience twisters every month and have some of the deadliest tornado outbreaks. However, Alabama sees more tornadoes than Oklahoma because of cool-season twisters.
Spring may be the South’s tornado season, but a second wave occurs between November and December, extending until February. Many still underestimate this long season because the Plains tally a severe yet few outbreaks over the year.
The Southern part of the US experiences longer and deadlier tornado outbreaks. The population density here is higher than on the plains. And its level of urbanization is the perfect ingredient for producing atmospheric instability.
Death tolls are also higher due to poverty and weaker homes. Southern homes do not have tornado shelters the same way Oklahoma does. Add that to the tornadoes’ increased speed and coverage in the cold season.
Tornado Alley and Dixie Alley both experience tornadoes. But because of climate change and population density, the Southeast part of the US experiences longer and deadlier twisters.
Want to know more about Tornado Alley’s shift? Leave your questions in the comment below.
If you reside in Tornado Alley or Dixie Alley, it will help to:
- Choose a sturdy room at home to make it your safe spot.
- Monitor current weather conditions in your area using Davis 6250 Weather Station.
For more great info like this, check out our guide to what country has the most tornadoes.