PlainHazard

Tornado Alley, measured

NOAA Storm Prediction Center tornado database, tornadoes rated F1/EF1 or stronger, 1950-2025

Tornado Alley has no official boundary: the Storm Prediction Center calls it "a nickname in the popular media for a broad swath of relatively high tornado occurrence in the central U. S." In the record since 1950, the states with the most tornadoes rated 1 or higher per square mile are Mississippi, Louisiana and Oklahoma; one of the top 15 is a Plains state and 6 are in the Southeast, the area often called Dixie Alley. The Plains' share of these tornadoes fell from 34% in 1950-1989 to 25% since 1990, while the Southeast's rose from 20% to 29%.

By  · Updated  · How this was measured

What is Tornado Alley?

"Tornado Alley is a nickname in the popular media for a broad swath of relatively high tornado occurrence in the central U. S. Various Tornado Alley maps which you may see can look different because tornado occurrence can be measured many ways--by all tornadoes, tornado county-segments, strong and violent tornadoes only, and databases with different time periods." It adds: "Violent or killer tornadoes do happen outside this Tornado Alley every year."
NOAA Storm Prediction Center, The Online Tornado FAQ

Source: NOAA Storm Prediction Center, The Online Tornado FAQ. SPC's tornado FAQ.

Where tornadoes began, in two eras

Each hexagon counts the tornadoes rated F1/EF1 or stronger that began inside it. The two maps share one colour scale.

1950-1989

  • 1-2
  • 3-7
  • 8-16
  • 17-26
  • 27+
Tornadoes rated 1 or higher by the hexagon they began in, 1950-1989 (40 years).

1990 to 2025

  • 1-2
  • 3-7
  • 8-16
  • 17-26
  • 27+
Tornadoes rated 1 or higher by the hexagon they began in, 1990-2025 (36 years).

Source: NOAA Storm Prediction Center tornado database, 1950-2025, track start points. SPC severe weather database.

Tornado Alley states, by the record

The 15 states with the most tornadoes rated F1/EF1 or stronger per 10,000 square miles of land since 1950:

  1. Mississippi 428 (2,007 tornadoes)
  2. Louisiana 394 (1,701 tornadoes)
  3. Oklahoma 372 (2,550 tornadoes)
  4. Alabama 355 (1,799 tornadoes)
  5. Indiana 327 (1,172 tornadoes)
  6. Arkansas 298 (1,551 tornadoes)
  7. Illinois 297 (1,649 tornadoes)
  8. Iowa 294 (1,641 tornadoes)
  9. Florida 277 (1,484 tornadoes)
  10. Delaware 262 (51 tornadoes)
  11. Tennessee 241 (994 tornadoes)
  12. Maryland 240 (233 tornadoes)
  13. Georgia 239 (1,380 tornadoes)
  14. Missouri 237 (1,632 tornadoes)
  15. Kentucky 232 (918 tornadoes)

Source: NOAA Storm Prediction Center tornado database (state segments rated 1 or higher), 1950-2025; land area: Census Bureau 2024 Gazetteer. SPC severe weather database.

How this was measured

Tornado density by state: every SPC state segment rated F1/EF1 or stronger since 1950, per 10,000 square miles of land (Census Bureau 2024 Gazetteer; states of 1,000 square miles or more). The maps place each tornado rated 1 or higher at the point where it began, in hexagons about 50 miles across, for 1950-1989 and for 1990 to 2025, on one colour scale. The weakest tornadoes (F0/EF0) are left out because their reporting rose with the Doppler radar network of the 1990s, as SPC notes. The regions are the same state groups as in the eastward-shift study.

Sources

NOAA Storm Prediction Center, Severe Weather Database, 1950-2025; SPC Online Tornado FAQ (read October 7, 2026); Census Bureau 2024 Gazetteer land areas; state lines: Census Bureau cartographic boundaries (2017), via us-atlas.

Limits

State densities average over a whole state: a state's western and eastern halves can differ more than two states do. Start points place a long track where it began, not where it did its damage.

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