Tornado Alley is the informal name for a broad region of the central United States that experiences more tornadoes per square mile than anywhere else on Earth. It has no official boundaries, but its heart runs through Texas, Oklahoma, Kansas, Nebraska, South Dakota, and parts of Colorado and Iowa.
Because there is no official definition, meteorologists disagree on the exact boundaries. The traditional core — as originally described by US Air Force meteorologists in 1952 — includes:
Broader definitions extend into Colorado, Iowa, Missouri, and parts of Minnesota.
Tornado Alley sits at the collision zone of three distinct air masses that meet more reliably here than anywhere else on Earth:
When these air masses collide during spring and early summer, they produce the wind shear and instability that generates supercell thunderstorms — the parent storms of nearly all violent (EF3+) tornadoes. Nowhere else on Earth combines these three air masses over such flat terrain, which allows storms to organize into large, long-lived supercells.
| State | Avg/year | Rank |
|---|---|---|
| Texas | ~140 | 1 |
| Kansas | ~95 | 2 |
| Oklahoma | ~65 | 3 |
| Nebraska | ~55 | 4 |
| Florida | ~50 | 5 |
| Missouri | ~45 | 6 |
| Illinois | ~55 | — |
| Alabama | ~50 | — |
| Iowa | ~50 | — |
| Mississippi | ~45 | — |
Based on 30-year averages from NOAA Storm Prediction Center data.
Since the 2000s, meteorologists have increasingly recognized a second high-tornado region: Dixie Alley, covering Mississippi, Alabama, Louisiana, Arkansas, Tennessee, and parts of Georgia. Dixie Alley produces fewer tornadoes per year than Tornado Alley — but on average, its tornadoes are deadlier.
Why Dixie Alley tornadoes kill more people per event:
The 2011 Super Outbreak — which produced Tuscaloosa 2011, Hackleburg 2011, and Smithville 2011 — hit Dixie Alley squarely.
Research published since 2018 (Gensini & Brooks, 2018 among others) shows the highest tornado frequency has been gradually shifting east since the 1980s — away from the traditional Tornado Alley core in the western Plains and toward the Mid-South and Dixie Alley states. Reasons include:
Whether this represents a permanent climate-driven shift or a short-term fluctuation is still actively debated.
Peak tornado activity in Tornado Alley runs from April through June, with a secondary peak in November for parts of the southern Plains. Roughly 75% of all US tornadoes occur between March and July. Dixie Alley has a bimodal season — spring (March–May) and fall (October–December).
→ Simulate a tornado anywhere in Tornado Alley