Just remember how big Texas is. One thing I did find while researching is that Kansas has had the highest number of F-5/EF-5 tornadoes since 1900.

Another reason why Tennessee, as well as places like Arkansas, northern Alabama, and southern Missouri, have so many people killed is that no one can see a twister coming. All those hills and trees take away your line of sight even if you are out in the middle of nowhere. Whereas with Kansas, the western 2/3 of Oklahoma, and Texas you can see 10 or more miles away on the horizon.