South Dakota tornadoes

Are tornadoes common in South Dakota?

South Dakota averages about 25 tornadoes a year since 2000, 16th of 52 states and territories by count. The busiest year on record was 1993 (85). Per 10,000 square miles of land, South Dakota records 258 tornadoes since 1950, 26th of 51 states and territories by that measure.

1. 1. Florida 701
2. 2. Oklahoma 658
3. 3. Mississippi 614
4. 4. Louisiana 579
5. 5. Illinois 567
6. 6. Kansas 564
7. 7. Iowa 555
8. 8. Alabama 537
9. 9. Indiana 492
10. 10. Maryland 438
11. 26. South Dakota 258

Source: NOAA SPC, tornadoes 1950-2025, per 10,000 square miles of land area (Census Bureau 2024 Gazetteer; places under 1,000 square miles not ranked). Damage colours: Storm Events damage, 2025 dollars.

Which counties in South Dakota have the most tornadoes?

Per square mile, Clay County leads South Dakota: 22 days with a tornado record since 1950, 53.4 per 1,000 square miles of land. By raw count, Brown County has the most tornado records (84 since 1950); large counties collect more records simply by covering more ground, so the ranking counts days with a record per unit of area (a storm filed for several forecast zones adds several records but one day).

1. Clay County 53.4 (31)
2. Lincoln County 48.5 (61)
3. McCook County 47.0 (42)
4. Davison County 45.9 (24)
5. Minnehaha County 45.9 (48)
6. Codington County 42.2 (35)
7. Turner County 42.1 (45)
8. Douglas County 41.7 (25)
9. Union County 41.2 (24)
10. Hutchinson County 40.6 (45)
11. Bon Homme County 39.0 (26)
12. Yankton County 38.4 (29)

Source: NOAA NCEI Storm Events Database, days with a record in the county since 1950 per 1,000 square miles of land (Census Bureau 2024 Gazetteer); in brackets, the count of records.

When is tornado season in South Dakota?

62% of its tornadoes since 1950 fell in May and June. The busiest month is June (776 tornadoes).

Source: NOAA Storm Prediction Center tornado database, state segments by the month they began, 1950-2025.

What were the deadliest tornadoes in South Dakota?

Source: NOAA Storm Prediction Center tornado database (state segments: deaths and path inside South Dakota), 1950-2025; counties are the first four the SPC lists for the segment. SPC severe weather database.

Where have the strongest tornadoes tracked in South Dakota?

Source: NOAA Storm Prediction Center tornado database, 1950-2025, start and end points of each track; county lines: Census Bureau cartographic boundaries (2017), via us-atlas. SPC severe weather database. Census cartographic boundary files.

The strongest tornadoes in South Dakota

Source: NOAA Storm Prediction Center tornado database; F scale before February 1, 2007, EF scale after.

The longest tornado paths in South Dakota

Source: NOAA Storm Prediction Center tornado database, state segments: path length and width inside the state. SPC severe weather database.

Tornadoes in every South Dakota county

Source: NOAA Storm Prediction Center tornado database: whole tornadoes whose track touched the county (any state segment listing it). SPC severe weather database.

Is South Dakota in Tornado Alley?

Tornado Alley has no official boundary; the Storm Prediction Center calls it a media nickname for the central U.S. area of relatively high tornado occurrence. By the record, South Dakota ranks 31st of 50 states for tornadoes rated 1 or higher per square mile since 1950 (99 per 10,000 square miles), and it is one of the Plains states at the core of the area the name usually means.

Tornado Alley, measured: the states by density and maps of where tornadoes began in two eras.

Source: NOAA Storm Prediction Center tornado database and Online Tornado FAQ. SPC's tornado FAQ.

The costliest tornadoes in South Dakota

Before 1993 NOAA filed damage by category, not amount, so the list above starts in 1993. The highest category filed here before then (entered as $25M, in the dollars of the day) holds: July 14, 1970 (tornado, Lincoln County, 1 killed); June 16, 1992 (tornado, Buffalo County).

Source: NOAA NCEI Storm Events Database: property and crop damage as estimated by the National Weather Service, in 2025 dollars.

Are tornadoes becoming more frequent in South Dakota?

South Dakota's count per decade against the whole country's, and its share. The Storm Prediction Center notes that tornado reports rose especially around the installation of the NEXRAD Doppler radar network in the mid-1990s, so a rising count is partly better detection; the share of the national total is the fairer comparison across decades.

Source: NOAA Storm Prediction Center tornado database, state segments.

The most recent tornadoes in South Dakota

Source: NOAA NCEI Storm Events Database, records through June 30, 2026; the newest months are revised by NCEI as reports arrive. Search the record at NCEI.

Federal disaster declarations for tornadoes in South Dakota

FEMA has declared 16 disasters in South Dakota for tornadoes, counting its incident type and declarations that name tornado in the title (FEMA files most storm disasters under Severe Storm); 16 were major disasters, the latest on September 1, 2026.

Source: FEMA OpenFEMA Disaster Declarations Summaries (v2), through October 2, 2026. OpenFEMA dataset page.

Next

• Clay County: the county's whole recordThe South Dakota county with the most tornadoes per square mile
• Tornadoes across the United StatesEvery state ranked, by year and month
• Every natural hazard in South DakotaTornadoes, floods, storms, heat and the federal declarations
• Hail in South Dakota17,011 records
• Severe thunderstorm wind in South Dakota12,755 records
• Winter storms in South Dakota10,128 records