Is Tornado Alley Expanding?

A recent article in the USA Today really got me thinking about tornadoes in the United States. Popularity seems to be at an all time high with these storms with more and more people taking an interest in both spotting and chasing severe weather. The report in the USA today claims that a new Tornado Alley should be extended much further east covering all of Illinois, Indiana and even here in Western Ohio. Here is the link to the story:

This “expanding” of tornado alley doesn’t really come as news though, tornadoes have always been prevalent in these parts of the country. This is the way it’s always been! We know that the best conditions year after year for the most powerful tornadoes are in the plains, but that doesn’t mean these storms can’t develop in other places (Xenia F-5 tornado, Van Wert EF-4 tornado).

But what the public needs to consider here is that people and technology are looking for tornadoes now more than ever, which is leading to this “expansion” of tornado alley! For example, fifty years ago a weak EF-0 tornado in the middle of a corn field wouldn’t have gotten reported because nobody cared, or no one was there to see it. Today with technology and more eyes to the sky, these tornadoes get reported and recorded into the system. Don’t get me wrong, this is a great thing that there is more awareness and recognition of these storms. But don’t let the hype fool you into thinking that the increase in tornadoes doesn’t have anything to do with increased reporting in this digital age where everyone has a easy access to things like cell phone cameras and the internet to spread the word quickly. Here is a graphic from the National Weather Service (NWS) showing a steady increase in tornadoes over the years.

If you only saw this graphic you would think, “Uh Oh! This doesn’t look good!” But before jumping to conclusions, consider this graph also from the NWS showing an increase in reported EF-0  tornadoes through the years.

What is very obvious to me based on the data provided in these two graphs is that the  correlation between the number of total tornadoes over the years has risen in part because a greater number of smaller tornadoes being reported due to recent advances in technology. While the overall number of tornadoes has gone up, the total number of more powerful storms has basically stayed the same. The overall strength of tornadoes has shown little change over the years.

Below is a graphic of strong to violent tornadoes in the US since 1950. (EF-3 to EF-5 tornadoes)

The trend is pretty steady with the highest point being in 1974 for the Super Outbreak.  The point I want to reiterate is that tornado alley has always consisted of a larger area than depicted in most maps, however, this recent development comes in large part due to increased reporting and new technologies.



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