MEMPHIS, TN (WMC) - New data is showing a change in the pattern which is the reason for the shift of the frequency of tornadoes southward.
This year’s tornado season is already off to a busy start as more than 200 tornadoes have already occurred this season. Around 1,200 tornadoes hit the nation annually according to National Severe Storms Laboratory. More than 70 fatalities in America each year by tornadoes, according to studies based on data from 1985 to 2014.
There have been more tornadoes lately east of the Mississippi and while that doesn’t mean that the tornado threat across the mid-west will end, it is a notable change especially for the Mid-South. There has also been in uptick in big tornado outbreaks too. In one study defining an outbreak as having six or more tornadoes within a six-hour period. The study also found that there are more EF1 or stronger tornadoes in these bigger outbreaks compared to those in the 1950s.
According to research, the number of days with thirty or more tornadoes has also increased. As if all those frightening facts weren’t enough, tornadoes in the Southeast also tend to be deadlier than those in the Plains because of several factors such as longer, larger tornado paths, larger population, more mobile homes and more rain wrapped and nighttime tornadoes.
Other changes of note are the changes in time of year that tornadoes occur. From November through February, tornadoes have increased across the southeast which of course includes the Mid-South. More tornadoes are occurring more at night which makes it harder to see and more dangerous. Studies show that night-time tornadoes produce more fatalities.
Although Tornado Alley still remains the top U.S. area for tornadoes, areas to the east are catching up, based on data from 1979 to 2017. That includes portions of Mississippi, Alabama, Arkansas, Missouri, Illinois, Indiana, Tennessee and Kentucky.
Tornadoes in the Southeast also tend to be deadlier than those in the Plains because of several factors such as longer, larger tornado paths, expanding population, more mobile homes and more nighttime tornadoes.
On average, about 40 people die each year in the nine states that make up the southeast. Alabama usually sees the most fatalities based on data collected from the storm prediction center.
An average of 10 people die from twisters each year combined in Texas, Oklahoma and Kansas, three states that make up most of Tornado Alley. Overall, more than 70 Americans nationwide are killed each year by tornadoes, based on data from 1985 to 2014.
This data was provided by Michael Tippett and Chiara Lepore for providing SPC tornado count data. Tornado climatology is based on Gensini and Brooks (2018). Special thanks to Harold Brooks and Victor Gensini for their guidance with this Climate Matters.