What the Heck is "Tornado Alley" Anymore?

Have you ever noticed that every map of Tornado Alley is different?

No two graphics depicting the region in the central U.S. where tornadoes historically occur most frequently are the same. A quick Google image search pulls up a ton of samples, none of which have exactly the same outline.

Accuweather.com has several maps like the one above indicating where their meteorologists believe Tornado Alley lies. I say "their meteorologists" because Tornado Alley is an arbitrary thing. It's an imaginary blob including several states where tornadoes historically impact with seasonal reliability and ferocity. Granted, it's an imaginary blob we've been using as a social reference point for 50 years, but still. 

In that time, we've learned so much about severe weather and how to forecast it. We've learned that tornadoes, and the storms which spawn them, aren't limited to just the Great Plains. That's where you're more likely to see photogenic storms, out in the middle of the prairies, but the more sparsely-populated region lying between the Rocky Mountains and the Mississippi River is not the only place where you're liable to see a nasty tornado.

Once again, Accuweather has a graphic for that. The private weather company labels Tornado Alley as a shifting entity, something that's morphing at the whims of a changing climate. I've seen other media outlets and weather blogs publish a similar story: Tornado Alley is moving to the east.

That's a load of hogwash, if I may say. Not in the sense that Tornado Alley is shifting, but in the idea that climate change is making tornadoes a more common phenomenon in states further south and east, like the Ark-La-Tex region, Mississippi, Alabama, and parts of Tennessee and Kentucky. They've always occurred, we're just getting better at forecasting and recording them.

It's our subliminal association based on decades of media consumption that limits our thinking about tornadoes in the contiguous United States. It wasn't that long ago that the word "tornado" was banned by the U.S. Weather Bureau because of fears it would cause panic among the public. Today we're observing and reporting more tornadoes occurring in regions outside of the central U.S., and most of that is because we have more tools available to do so -- like improved radar tracking and smart phones in most peoples' pockets -- but there is a climate change factor that is sourcing more moisture from the Gulf of Mexico to fuel stronger storms in southern states, further blending our imagined boundaries.

A study conducted in 2010 by P. Grady Dixon, a physical geographer at Fort Hays State University, found the county in the U.S. that's the most tornado-prone isn't in Kansas or Oklahoma. It's Smith County, Miss., with 1.38 tornado days on average per year within 25 miles of a point. Dixon's research also determined that tornadoes occurring within the Smith County area had "considerably longer path lengths" than some Great Plains counterparts, meaning this little stretch of Mississippi has a 35% greater tornado density than Oklahoma County, Okla., which only had 1.02 tornado days on average per year.

In a Washington Post article from 2020, Dixon said he feels the term "Tornado Alley" is too restrictive or outdated. Aside from a small portion of southern Missouri and the Arkansas Ozarks (which aren't completely immune to tornadoes), he said there's virtually nothing distinguishing what we know as traditional Tornado Alley with the poorly-nicknamed "Dixie Alley" in the South.

The above graphic courtesy Severe Weather Europe shows what some scientists consider to be the modern "alleys" for tornado frequency. There's a stretch of the Upper Midwest and a spot among the Carolinas that also sees tornadic activity from time to time. Again, I feel this type of map is misinforming, potentially leading people in areas that aren't specifically outlined to think they won't be affected by severe weather. Again, optimism bias rears its head with, "it can't happen to me, I don't live anywhere near Tornado Alley."

I've written in a previous blog post that, depending on where you live, being impacted by a destructive storm is only a matter of time, and it's up to you to be prepared for it. In the future I hope severe weather education gets boosted in other parts of the country that experience tornadoes to the level it is in Kansas and Oklahoma. 

For those of us who live in Kansas or Oklahoma, Tornado Alley is a sort-of branding device or marketing campaign, if you will. It's part of our identity as a region, engrained in pop culture and spoken of with a shred of mysticism. What kind of person would want to live in Tornado Alley? Sounds scary.

The nomenclature may sound frightening, sure. What's scarier to me is the reality of a violent 2.25-mile-wide tornado, made invisible by rain and trees, churning through forests and neighborhoods at highway speeds. That particular tornado impacted parts of Mississippi in 2020. It would go on to become the third-largest tornado ever documented, after the Hallam, Neb. twister of 2004 and the infamous El Reno tornado of 2013.

There's a lot more research to be done on the severity of tornadoes which impact the South versus the Great Plains. As of right now, it's understood that twisters in southern states may be more destructive because of their ability to travel farther and faster, due to more available moisture in the atmosphere. Those storms also impact more people, not all of whom live in sturdy housing, nestled among all those hills and trees. The storms also continue later in the year, with a season lasting from September to about May. That overlaps with the severe weather season in the central U.S. that typically begins in April and lingers through June.

As usual, there's more work to do among the weather enterprise to improve education and social understanding of severe weather in places that aren't used to seeing it. In time, I believe attitudes and mindsets about tornadoes will change as our knowledge base grows.

And no, I'm not interested in chasing storms in the South. I've done it once before in Arkansas, in the dark, among mostly forested terrain. That was enough.