Alabama’s “Severe Weather Awareness Week” rolls along on this Thursday (and we will do this for Tennessee later this month, as mentioned before). Today’s topic from the NWS Huntsville is concerning a weather hazard in our area that gets most if not all of the attention… Tornadoes. A tornado is defined as a windstorm comprised of a violently rotating column of air associated with a localized area of low pressure, with the rotating winds being in contact with both the ground and the base of the parent storm or updraft. Tornadoes get more attention in our area because they are so damaging and deadly. While it is true that lightning and flooding kill more people on average in a given year across the country, specifically in our part of the country once you add up all weather fatalities from over the years, cumulatively, tornadoes have killed more people here than any other weather hazard.
The tornado threat we face here in the Tennessee Valley and adjacent parts of the Southeast is a little unique from more “traditionally thought of” areas of the country that are at risk from tornadoes such as the Great Plains, because we have an enhanced frequency of them happening during a larger part of the year. In the Plains, while a tornado can technically happen in any month of the year, they are most frequently found between March and early June, with only a slight uptick in activity in the fall months. In the Southeast and Tennessee Valley, the heart of our tornado season runs from November to May, with enhanced activity occasionally starting as early as October or occasionally lasting into June some years. In addition, in those summer months outside of our core “tornado season”, we are still at risk from occasional tornado threats, mainly related to landfalling tropical storms and hurricanes.
In comparison to what is traditionally thought of as “Tornado Alley”, our portion of the country here in “Dixie Alley” sees a higher overall frequency of tornado fatalities than anywhere else in the United States. The above map from a study several years ago by Walker Ashley and associates showed that the highest frequency of tornado deaths in our country from 1950 to 2004 was in an area from east-central Arkansas, across western middle Tennessee, and covering the northern two-thirds of both Mississippi and Alabama, with a peak in that area running from the Memphis area over to northwest Alabama. It should be pointed out that those statistics stopped in 2004, prior to the Super Tuesday 2008 tornado outbreak that killed 57 people across the Mid-South or the 2011 Super Outbreak that killed 252 people in Alabama alone and over 300 in total. If this same study was to be done again to include more recent tornado events since 2004, that white maxed out zone would likely expand a good deal farther across north central Alabama, southern middle Tennessee, and north central to northeast Mississippi.
Tornadoes are so deadly in our portion of the country because a unique juxtaposition of several factors:
- Tornadoes in our area happen with a significant frequency in the cooler months, outside of when most people traditionally think tornadoes are most likely, despite what actual history says about tornado frequency in their area.
- Tornadoes in the Southeast are often rain-wrapped and harder to see coming until they are right up on you. Even our large, violent tornadoes usually are rain-wrapped fuzzy looking wedges instead of the clean-cut wedge tornadoes you can see from a few miles away. April 27, 2011’s clearly visible wedge tornadoes were a MAJOR exception to what is normal here.
- Tornadoes here are often obscured by thick tree cover and hilly terrain, making them even more difficult to see coming in advance.
- We have a substantial frequency of long-tracked EF3-EF5 intensity tornadoes here, per square mile, of a higher frequency than that of the Great Plains.
- Tornadoes here, because they happen in the fall, winter, and early/mid spring when jet stream winds are typically stronger, are often fast-moving. Tornadoes here can sometimes move at over 60 mph forward speed, giving people in the path little time to react.
- A significant portion of tornadoes here are quick spin-up tornadoes in squall lines that happen very quickly and sometimes with little to no warning because of their shallow nature and their ability to sometimes develop under the beam height of area Doppler Radars.
- A large number of our tornadoes happen during the nighttime hours, not only making them harder to spot, but when most people are asleep and unaware of what is happening anyway.
- Tornadoes in the Southeast target an area of the country whose population is more spread out versus that of the Plains. A tornado traveling through a rural area is here much more likely to still find homes per square mile than the same tornado traveling through a rural area of the Central Plains.
- A large portion of these rural areas of the Southeast have a significant mobile home population and are of a more challenging socioeconomic status, making people in these areas even more vulnerable to violent storms.
Because of the significant danger that tornadoes pose and the frequency in which they regularly happen in our part of the country, it is vitally important that you have a safety plan in place ahead of time, and you are actively aware of weather information when severe weather threats are in the forecast. In addition to the abundance of safety and preparedness information in the graphics above, here is a link to Monday’s discussion where we talk specifically about preparedness and severe weather safety in significant detail: https://tnvalleyweather.com/alabamas-2025-severe-weather-awareness-week-begins-mondays-topic-from-nws-huntsville-preparedness-and-safety
