South Dakota floods
Every recorded flood since 1996 · 66 counties with a record
NOAA's Storm Events Database records 3,390 floods and flash floods in South Dakota from 1996 through June 30, 2026, about 119 a year since 2000. The deadliest was the June 20, 2011 flash flood in Lyman County: 2 deaths. South Dakota ranks 23rd of 52 states and territories by count and 36th of 51 per square mile.
Floods in South Dakota, 1996 to 2026
Flood records per year (NOAA Storm Events); 2026 to June 30, 2026.
- recorded, no damage figure
- under $1 million
- $1 million or more
- $10 million or more
- $100 million or more, or 10 deaths
- $1 billion or more, or 100 deaths
- a year's colour: its recorded damage or deaths
- a year with a death
- Records
- 3,3901996 to June 30, 2026
- A year since 2000
- 119average
- Deaths
- 108 injuries
- Damage, 2025 dollars
- $1.4Bas filed
- Busiest year
- 2019790 records
Source: NOAA NCEI Storm Events Database, records through June 30, 2026; deaths and damage as filed, damage in 2025 dollars. Search the record at NCEI.
Are floods and flash floods common in South Dakota?
South Dakota averages about 119 floods and flash floods a year since 2000, 23rd of 52 states and territories by count. The busiest year on record was 2019 (790). Per 10,000 square miles of land, South Dakota records 447 floods and flash floods since 1996, 36th of 51 states and territories by that measure.
Source: NOAA NCEI Storm Events Database, records since 1996, 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 floods and flash floods?
Per square mile, Union County leads South Dakota: 107 days with a flood since 1996, 232.2 per 1,000 square miles of land. By raw count, Minnehaha County has the most flood records (230 since 1996); 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).
Source: NOAA NCEI Storm Events Database, days with a record in the county since 1996 per 1,000 square miles of land (Census Bureau 2024 Gazetteer); in brackets, the count of records.
When is flood season in South Dakota?
40% of its floods and flash floods since 1996 fell in May and June. The busiest month is June (816 records).
The values, month by month
Jan 14 · Feb 32 · Mar 448 · Apr 439 · May 555 · Jun 816 · Jul 424 · Aug 307 · Sep 237 · Oct 73 · Nov 25 · Dec 20 (records).
Source: NOAA NCEI Storm Events Database, records by the month they began, since 1996.
What were the deadliest floods and flash floods in South Dakota?
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2011-06-20 | Flash FloodLower Brule, Lyman County Very heavy rainfall of 5 to 7 inches brought flash flooding to mainly eastern Lyman county. Many roads were flooded with some washed out. Two women died in two separate vehicles after driving into a washed out portion of a road. One woman was found 100 yards downstream while the other woman was found 4 miles ... | 2 | 0 | – | |
| 2019-03-20 | FloodWoonsocket, Sanborn County Snow melt and heavy rainfall (measured 2.47 inches at Forestburg and 1.60 inches at Huron) resulted in extensive flooding of agricultural land and numerous township and county roads. The James River near Forestburg (gage site FORS2) reached a crest of 4.18 feet above flood stage on March 25. The driver and passenger ... | 2 | 0 | – | |
| 2014-06-17 | Flash FloodCastle Rock, Butte County Battle Creek flooded US Highway 85 north of Belle Fourche. A vehicle was swept away by the flowing water; one person had minor injuries but walked to the highway, the other was not found and is presumed dead. | 1 | 1 | – | |
| 2012-05-05 | Flash FloodOrland, Lake County Heavy rainfall of up to 6 inches caused flash flooding of numerous roads, parks, fields, other low areas, and buildings including homes. At least 90 homes were heavily damaged in Madison by the flooding, including at least two with basement walls washed out. A basement wall of a dentists business was also washed out ... | 1 | 0 | $2.6M | |
| 2008-06-11 | FloodHiland, Grant County On the north fork of the Yellowbank Creek southeast of Milbank, a woman died when she went around a barricaded road with her car in the early morning hours of the 12th. Her car was found 200 yards from the road. | 1 | 0 | – | |
| 2024-06-20 | FloodBeresford, Lincoln County One storm episode: 14 records in 14 places, 2024-06-20 to 2024-06-21; the totals are the episode's. A multi-day significant heavy rainfall event from June 20-22 resulted in widespread rain totals between 5 and 10 inches with pockets in excess of 15 inches across portions of southeast South Dakota, northwest Iowa, and southwest Minnesota. As rainfall reached area streams and rivers, major to record flooding was ... | 1 | 0 | $94M | |
| 2022-07-01 | FloodBrentford, Spink County On Friday, July 22nd, a 13-year-old girl was swept downstream while swimming in the James River near Frankfort. The search was postponed around 11:30 p.m. Friday due to the dangers of the current and the inability to see in the dark. The girl's body was found around 9:25 a.m. on Saturday. | 1 | 0 | – | |
| 2019-04-01 | FloodLoomis, Davison County Runoff from occasional precipitation in late March and April maintained considerable flooding throughout the flood plain across Davison county. 416th Avenue near Rosedale Colony and 257th Street near the gage site were impacted by water. A direct fatality to a 22 year-old male occurred early on April 3, when his ... | 1 | 0 | – |
Source: NOAA NCEI Storm Events Database: deaths direct and indirect, as filed by the National Weather Service, summed over each storm (one episode, or one named storm filed by several offices). Storm names from the titles of FEMA declarations that name the storm's counties.
The costliest floods and flash floods in South Dakota
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2019-06-01 | FloodTripp, Hutchinson County One storm episode: 24 records in 24 places; the totals are the episode's. | 0 | 0 | $712M | |
| 2019-06-01 | FloodMansfield, Spink County One storm episode: 26 records in 26 places; the totals are the episode's. | 0 | 0 | $354M | |
| 2024-06-20 | FloodBeresford, Lincoln County One storm episode: 14 records in 14 places, 2024-06-20 to 2024-06-21; the totals are the episode's. | 1 | 0 | $94M | |
| 2005-07-01 | FloodMarshall County · forecast zone Marshall One storm episode: 3 records in 3 places; the totals are the episode's. | 0 | 0 | $34M | |
| 2019-03-13 | FloodUtica, Yankton County One storm episode: 20 records in 20 places, 2019-03-13 to 2019-03-14; the totals are the episode's. | 0 | 0 | $33M | |
| 2019-09-12 | FloodMetzgerville, Davison County One storm episode: 15 records in 15 places; the totals are the episode's. | 0 | 0 | $27M | |
| 2019-04-01 | FloodJamesville, Yankton County | 0 | 0 | $23M | |
| 2004-06-16 | Flash FloodSioux Falls, Minnehaha County | 0 | 0 | $16M |
Source: NOAA NCEI Storm Events Database: property and crop damage as estimated by the National Weather Service, in 2025 dollars.
Are floods and flash floods becoming more frequent in South Dakota?
South Dakota's count per decade against the whole country's, and its share. NOAA recorded every event type only from 1996, so earlier decades are not comparable; the share of the national total is the fairer comparison across decades.
| Decade | South Dakota | United States | South Dakota's share |
|---|---|---|---|
| 1996-99 | 278 | 20,986 | 1.3% |
| 2000s | 549 | 54,913 | 1.0% |
| 2010s | 1,922 | 68,322 | 2.8% |
| 2020-26 | 641 | 43,563 | 1.5% |
Source: NOAA NCEI Storm Events Database.
The most recent floods and flash floods in South Dakota
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2026-06-29 | FloodFt Pierre, Stanley County | 0 | 0 | – | |
| 2026-06-05 | FloodBruce, Brookings County | 0 | 0 | – | |
| 2026-06-04 | FloodBruce, Brookings County | 0 | 0 | – | |
| 2026-06-03 | Flash FloodClear Lake Municipal Airport, Deuel County | 0 | 0 | – | |
| 2026-06-02 | Flash FloodRed Shirt, Oglala Lakota County | 0 | 0 | – | |
| 2026-06-02 | FloodSlim Butte, Oglala Lakota County | 0 | 0 | $1.3M | |
| 2026-06-02 | Flash FloodSlim Butte, Oglala Lakota County | 0 | 0 | $1.3M | |
| 2026-06-02 | Flash FloodFolsom, Custer County | 0 | 0 | – | |
| 2026-06-02 | Flash FloodCedar Pass, Jackson County | 0 | 0 | – | |
| 2026-05-31 | Flash FloodLeola, McPherson County | 0 | 0 | – | |
| 2026-05-31 | Flash FloodAlexandria, Hanson County | 0 | 0 | – | |
| 2026-05-31 | Flash FloodHumboldt, Minnehaha County | 0 | 0 | – |
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 floods and flash floods in South Dakota
FEMA has declared 46 disasters in South Dakota for floods and flash floods, counting its incident type and declarations that name flood in the title (FEMA files most storm disasters under Severe Storm); 46 were major disasters, the latest on September 1, 2026.
| Declared | Number | Title | Areas named |
|---|---|---|---|
| 2026-09-01 | DR-4941 | Severe Storms, Straight-Line Winds, and Flooding | 1 |
| 2026-09-01 | DR-4938 | Severe Storms, Straight-Line Winds, Tornadoes, and Flooding | 10 |
| 2025-09-11 | DR-4890 | Severe Storm and Flooding | 1 |
| 2024-11-01 | DR-4842 | Severe Storm, Straight-Line Winds, and Flooding | 1 |
| 2024-08-15 | DR-4807 | Severe Storms, Straight-Line Winds, and Flooding | 25 |
| 2023-07-06 | DR-4718 | Flooding | 11 |
| 2022-08-02 | DR-4664 | Severe Storm, Straight-Line Winds, Tornadoes, and Flooding | 6 |
| 2022-06-29 | DR-4656 | Severe Storm, Straight-Line Winds, Tornadoes, and Flooding | 22 |
| 2019-11-18 | DR-4469 | Severe Storms, Tornadoes, and Flooding | 25 |
| 2019-10-07 | DR-4467 | Severe Storms, Tornadoes, and Flooding | 8 |
| 2019-09-23 | DR-4463 | Severe Storms and Flooding | 27 |
| 2019-06-20 | DR-4448 | Severe Winter Storm, Snowstorm, and Flooding | 1 |
Source: FEMA OpenFEMA Disaster Declarations Summaries (v2), through October 2, 2026. OpenFEMA dataset page.
Next
- Union County: the county's whole recordThe South Dakota county with the most floods and flash floods per square mile
- Floods 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