As we leave the festive season behind and move towards the beginning of spring, professional meteorologists start to concentrate less on those winter storms and start focusing more on severe weather occurrences.
You can start to see evidence of severe weather from as early as March but it’s really closer to May and through till June that tornado season really kicks into full force. Especially in ‘Tornado Alley.’
However, where these natural weather occurrences start to form seem to be shifting slightly towards the east.
Now, don’t get me wrong, Tornado Alley will still see its fair share of these vortexes of violently rotating winds, but recently there has been a decrease in the number of tornadoes here.
Unfortunately, that doesn’t necessarily mean that there are fewer tornadoes and twisters forming.
A wide birth of space between Illinois and Louisiana has seen an increase in tornadoes recently. In fact, in December 2021 the Quad State Tornado was well over 200 miles east of the area aptly named ‘Tornado Alley.’
What Is A Tornado?
A tornado is a center of low pressure that stretches from the ground all the way up into the cloud base. This then draws air into its core coming from all directions.
The air then picks up speed and swirls around in a vortex. If you’ve ever watched the water drain from a bath once you’ve pulled the plug, it is very similar to that except much bigger and a whole lot more powerful and destructive.
Tornadoes can come in many different shapes and sizes and can range in intensity. Thankfully approximately 75% of all tornadoes are fairly weak with winds that reach less than 110 mph (180 kph).
However you can also get much wider, taller, more violent tornadoes can reach over 200 mph (321 kph)
Violent tornadoes only account for 2% of all tornadoes, and yet they have still caused around 70% of all US tornado deaths since 1950.
What Is Tornado Alley?
Tornado Alley refers to an area of land in the USA, around South Dakota and upwards towards Texas, where tornadoes most frequently occur (see also ‘Tornado Season In Texas: Detailed Guide‘).
These tornadoes are often more powerful than tornadoes that you’ll see in other areas of the United States and can be considerably more destructive.
There aren’t exactly clear or defined borders for exactly where Tornado Alley is, however it mainly extends from Northern Texas and then covers, Oklahoma, Kansas, Nebraska, Iowa, and South Dakota.
However, there are a few more states that are sometimes classed as Tornado Alley due to their proximity, and these include Minnesota, Wisconsin, Illinois, Indiana, Missouri, Arkansas, North Dakota, Montana, and Ohio.
Where Did The Term ‘Tornado Alley’ Come From?
Meteorologists and storm chasers have been aware of the severe weather that affects the Great Plains long before this term was used.
However, it wasn’t until 1952 that the term ‘Tornado Alley’ came about.
It was during this year that two esteemed meteorologists Major Ernest J. Fawbush and Captain Robert C. Miller did a study on the severe weather occurrences in this area and titled their paper ‘Tornado Alley’ ever since the name has stuck, and we still refer to the area by the name even now.
Why Is Tornado Alley So Prone To Tornadoes?
Tornado Alley sits on the Southern end of a continent that stretches from the cool Arctic to the hot Tropics.
This massive landmass allows dense polar air to move southward, and since there is no mountain range hot humid air that comes from warmer countries such as the Caribbean this warmer air advances towards that cooler polar air.
While this happens, air from the west of the alley comes from the Rocky Mountains. This dry mountain air comes down the mountain and pushes east towards the Great Plains.
This forms what is called the ‘Dryline.’ Whereas the air on the west is similar to the scorching desert air which can often be accompanied by blowing dust (also see ‘The Importance Of The Weather In A Desert Climate‘).
All this air collides together and creates the exact conditions needed to create storms.
Why Is Colling Air So Significant?
All the different types of colliding air masses that we see at tornado alley create the perfect conditions for energetically ascending air – which is exactly what is needed for thunderstorms.
Thunderstorms can then easily be escalated into tornadoes given the right conditions.
Because this area of America has constantly colliding air, the probability of tornadoes increases significantly. While the air doesn’t always result in tornadoes, and sometimes just storms, there is a much higher chance of these tornadoes forming.
When these supercell thunderstorms do occur they can create tornadoes that have an F2 or greater force which is much greater in speed and strength than anything you’ll be likely to see in European countries for example where the average tornado is only F0 to F1 at the most (also see ‘Do European Countries Experience Tornadoes? Everything You’ll Need To Know‘).
Can Tornadoes Occur Anywhere In The US?
They can, and they do. The United States actually has more tornadoes than any other country across the globe, in fact, there are more tornadoes in the USA than Canada, Australia, and every European country combined.
And it’s not just in Tornado Alley that they happen. There are approximately 1150 tornadoes in America each year and every single state has experienced at least one tornado, some even have over a dozen a year.
Many meteorologists actually dislike the term ‘Tornado Alley’ as many people then presume that this is the only area in America that experiences tornadoes and this simply just isn’t true.
Both the Great Lakes and the southeast of the United States are at high risk of tornadoes.
Is Tornado Alley Shifting East?
According to research, yes, it is.
In 2018, a study showed evidence that throughout the past forty years or so tornado frequency has continued to decline, while just across to the east of tornado alley, severe weather occurrences have significantly increased through places such as the Deep South and the Lower Great Lakes.
Generally, it was always closer to Dallas that people worried about tornadoes wreaking havoc however the study actually suggests that its states such as Memphis or Nashville that have the most cause for concern.
And this point has been proven true as during March of 2020, a tornado ripped through Nashville. Memphis has also recently seen quite a lot of tornadic activity.
This region has also recently been named ‘Dixie Alley’ which is a subtle nod to the climbing number of tornadoes that are ripping through the South.
Has Climate Change Caused The Shift?
Thanks to Doppler radar coverage, meteorologists do have a much better ability to detect tornadoes even when there is no evidence or ‘ground truth’ to verify it.
Of course, if tornadoes are now becoming easier to detect, it’s likely that numbers will increase as you’ll now be picking up activity that was once missed. Dixie Alley is also significantly more populated than Tornado Alley and this also makes detection much easier.
But the increase is just too severe for that to be the sole reason for the higher numbers. So something else is also at work to push these tornadoes towards the east.
But what is it? No one is 100% sure, but it’s very likely that climate change is to blame. So the next question has to be is it man-made or natural climate change causing the shift?
One theory is that the jump up in tornadoes in Dixie Alley is due to an increase in tornadoes across the whole of America due to severe weather conditions which come from global warming.
In fact, this increase in severe weather occurrences has been predicted for several years.
There are other theories too. Another theory suggests that the increase in tornadoes comes from other factors such as the surface temperature of the Pacific sea.
This has the potential to be moving Tornado Alley, however, there just isn’t enough data yet to prove whether this is correct or not.
Staying Safe In A Tornado
1. Be Prepared
If you live in an area where tornadoes are likely you should always ensure that you are prepared. To stay safe during a tornado always ensure that you have the following:
A pack of batteries and a battery-operated radio, tv, or the like so that you can listen to any important emergency information.
An emergency plan for tornadoes including a place to stay for you, your family, and any pets.
An emergency kit with non-perishable foods, water, and any vital medication
A list of any important information or contact numbers that you may need.
2. Be Vigilant For Warning Signs
Tornadoes can happen very quickly and you may not have enough time to even notice any signs. However, there are always a few things that you can do, or look out for to try and stay prepared:
Check local radio stations or tv channels during storms that may progress into something worse.
A dark green sky
Extremely large hail
A loud roar that resembles a freight train
A singular very large, dark, low-hanging cloud
3. Know Where To Shelter
Falling or getting struck by flying debris cause the most injuries and deaths during a tornado, so knowing where to shelter is essential. While there is no completely tornado-proof place to shelter, some rooms and places are much better than others.
Pick a room on the lowest floor of the building such as the ground floors or basements.
Avoid any rooms with windows.
Hide under something sturdy such as a table and then cover yourself with a blanket or mattress.
Try and protect your head
Never stay in a mobile home
If you are outdoors you need to find the nearest building to take cover.
If you are in a car, evacuate it immediately and find cover in the nearest building, never try to outrun a tornado.
Final Thoughts
Regardless of the reason, one thing is for sure, tornadoes are shifting from tornado alley and towards the east. So if you live in these areas you may want to make sure that you are prepared for some tornadic activity.
Ensure that you have an emergency plan in place and always try and stay prepared as this may just save your life in the case of a real emergency.
However, while there are certainly more tornadoes in America than in any other country, try not to stress too much as 75% of tornadoes aren’t strong. And only 2% of tornadoes are actually violent.
This being said, any tornado has the potential to be destructive so having a plan in place is always a good idea. Better to have and not need than to need and not have!
Hi, my name is Andrew Capper and I have been a meteorologist for almost 30 years now. My line of work specializes in the scientific principles used to explain and understand the earth’s atmosphere and how that affects everyday life.
I created this website to share my knowledge and help others stay safe during extreme weather events.
I’ll be looking at weather forecasting, clouds, tornadoes, hurricanes, and much more - so, if you’ve ever been fascinated by the weather like I have been since I was a young boy, this is the site for you. Enjoy!
