Tornado Alley

Texas is in the “Tornado Alley” that includes several states. The weather term dates from at least 1948.
   
   
Wikipedia: Tornado Alley
Tornado Alley is a colloquial term most often used in reference to the area of the United States in which tornadoes are most frequent. It encompasses the great lowland areas of the Mississippi, the Ohio and lower Missouri River Valleys, as well as the Southeast. Although no state is entirely free of tornadoes, they are most frequent in the Plains area between the Rocky Mountains and Appalachians. Oklahoma, Kansas, Arkansas, Iowa, and Missouri are entirely within Tornado Alley, as well as Northeastern Texas, Eastern Colorado, Northern Louisiana, Central and Southern Minnesota, Central and Eastern parts of the Dakotas, Northwestern Mississippi, Central and Southern Illinois Southwestern Indiana, and parts of Central, southeast and southwest parts of Nebraska. Also small parts of far Western Tennessee and Kentucky are typically included as well as some parts of Wisconsin.
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Statistically, most U.S. tornadoes occur in Texas. When land area is taken into account, however, Florida has the highest density of tornado occurrence in the country [2]. Nearly all of these tornadoes are weak and not produced by supercell thunderstorms; Oklahoma has the highest occurrence of such “classic” tornadoes.
       
Google Books
Title: District of Columbia Appropriations for 1954, Hearings Before ... 83-1, on H.R. 5471
Publisher: 
Author(s): United States. Congress. Senate. Appropriations Committee
Publication Date: 1953
Pages: 654
It might amuse you to know that down in Texas when I was visiting the tornado disaster area, one of the Texas papers carried an editorial stating that it disliked to be referred to as “Tornado Alley.”
   
28 March 1948, Nevada State Journal (Reno, NV), pg. 1:
Twisters Rage Over
“Tornado Alley”
In Midwest 
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Once again the twister followed “tornado alley” up from the southwest, the high winds sweeping across Missouri, Illinois, doing most of their damage in Indiana, then splaying out into a dozen fingers.
     
23 March 1952, Chicago Daily Tribune, “207 Die in 8-State Storms,” pg. 2:
The tornadoes plunged into Arkansas thru “tornado alley,” given that name because of the frequence of the big winds in the past.
   
5 May 1957, New York Times, “Warning System for Tornadoes,” pg. 215:
Weather Bureau scientists are watching “Tornado Alley,” the incubator of nature’s deadliest storms, as never before.
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This year, the N.G.S. reports, more than 100 pressure-jump indicators are being operated in the severe-storm belt—Kansas, Missouri, Oklahoma and Texas.
   
26 May 1957, New York Times, pg. E2:
“Tornado Alley”
According to the U. S. Weather Bureau, tornadoes have occurred in every hour of the day, every month of the year, and every state. But most often they occur in May and June, between 4 and 7 P. M., in what has been called “Tornado Alley”—Texas, Oklahoma, Arkansas, Kansas, Missouri and Iowa.