States › South Dakota › Union County › Flood
Flood in Union County, South Dakota
160 floods and flash floods events in the NCEI Storm Events record, 1950 to 2026. Event types counted: Flood, Flash Flood, Coastal Flood, Lakeshore Flood.
NCEI notes that Storm Data is compiled from a variety of sources including the National Weather Service, other federal, state and local agencies, the media and the public; that property and crop damage figures are estimates; and that some events are recorded by NWS forecast zone rather than by county. FEMA notes that NFIP claim records are redacted and aggregated to protect the privacy of policyholders. Storm records through 30 Jun 2026.
Union County, South Dakota, has 160 flood events in the NCEI record since 1950, with at least one in 24 different years.
June is the busiest month, with 45 of the recorded events. The last 20 years account for 140 events against 20 in the 20 years before, a change that reflects reporting practice as much as weather.
The county holds 4.7% of the 3,390 flood events recorded in South Dakota; its 34.7 per 100 square miles compares with 4.5 statewide.
Compared with South Dakota
| Measure | Union County | South Dakota | US |
|---|---|---|---|
| Flood events since 1950 | 160 | 3,390 | 183,559 |
| Per 100 square miles | 34.7 | 4.5 | 5.2 |
| Per 10,000 residents | 94.8 | 37.9 | 5.5 |
| Deaths recorded | 0 | 10 | 2,961 |
| Busiest month | June | June | June |
By year
Seasonality
0Feb
2Mar
22Apr
22May
24Jun
45Jul
16Aug
3Sep
16Oct
10Nov
0Dec
0
Recorded events
All 160 events, most recent first. Magnitude is hail size, tornado rating or wind speed as recorded.
| Date | Event type | Magnitude | Property damage | Crop damage | Deaths | Injuries | Geography |
|---|---|---|---|---|---|---|---|
| 24 Jul 2025 | Flash Flood | — | — | — | — | — | County |
| 1 Jul 2024 | Flood | — | — | — | — | — | County |
| 1 Jul 2024 | Flood | — | — | — | — | — | County |
| 1 Jul 2024 | Flood | — | — | — | — | — | County |
| 24 Jun 2024 | Flood | — | — | — | — | — | County |
| 24 Jun 2024 | Flood | — | — | — | — | — | County |
| 23 Jun 2024 | Flood | — | — | — | — | — | County |
| 23 Jun 2024 | Flood | — | — | — | — | — | County |
| 23 Jun 2024 | Flood | — | — | — | — | — | County |
| 21 Jun 2024 | Flood | — | — | — | — | — | County |
| 21 Jun 2024 | Flood | — | — | — | — | — | County |
| 21 Jun 2024 | Flood | — | $55M | — | — | — | County |
| 20 Jun 2024 | Flood | — | — | — | — | — | County |
| 12 Apr 2023 | Flood | — | — | — | — | — | County |
| 10 Apr 2023 | Flood | — | — | — | — | — | County |
| 10 Apr 2023 | Flood | — | — | $17K | — | — | County |
| 16 Mar 2023 | Flood | — | — | — | — | — | County |
| 1 Apr 2020 | Flood | — | — | — | — | — | County |
| 1 Apr 2020 | Flood | — | — | $32K | — | — | County |
| 1 Apr 2020 | Flood | — | — | — | — | — | County |
| 30 Mar 2020 | Flood | — | — | — | — | — | County |
| 29 Mar 2020 | Flood | — | — | — | — | — | County |
| 29 Mar 2020 | Flood | — | — | — | — | — | County |
| 10 Mar 2020 | Flood | — | — | — | — | — | County |
| 10 Mar 2020 | Flood | — | — | — | — | — | County |
| 3 Oct 2019 | Flood | — | $5K | — | — | — | County |
| 1 Oct 2019 | Flood | — | $5K | — | — | — | County |
| 1 Oct 2019 | Flood | — | $5K | — | — | — | County |
| 1 Oct 2019 | Flood | — | $5K | — | — | — | County |
| 17 Sep 2019 | Flood | — | — | $5K | — | — | County |
| 16 Sep 2019 | Flood | — | $10K | — | — | — | County |
| 14 Sep 2019 | Flood | — | $25K | — | — | — | County |
| 13 Sep 2019 | Flood | — | $10K | — | — | — | County |
| 12 Sep 2019 | Flood | — | — | $382K | — | — | County |
| 12 Sep 2019 | Flood | — | $25K | — | — | — | County |
| 12 Sep 2019 | Flood | — | $10K | — | — | — | County |
| 2 Jul 2019 | Flood | — | — | — | — | — | County |
| 1 Jul 2019 | Flood | — | — | — | — | — | County |
| 1 Jul 2019 | Flood | — | — | — | — | — | County |
| 29 Jun 2019 | Flood | — | — | — | — | — | County |
| 28 Jun 2019 | Flood | — | — | — | — | — | County |
| 27 Jun 2019 | Flood | — | — | — | — | — | County |
| 27 Jun 2019 | Flood | — | — | — | — | — | County |
| 1 Jun 2019 | Flood | — | — | $11M | — | — | County |
| 1 Jun 2019 | Flood | — | — | — | — | — | County |
| 1 Jun 2019 | Flood | — | — | — | — | — | County |
| 1 Jun 2019 | Flood | — | — | — | — | — | County |
| 1 Jun 2019 | Flood | — | — | — | — | — | County |
| 1 Jun 2019 | Flood | — | — | — | — | — | County |
| 1 Jun 2019 | Flood | — | — | — | — | — | County |
| 1 Jun 2019 | Flood | — | — | — | — | — | County |
| 31 May 2019 | Flood | — | — | — | — | — | County |
| 30 May 2019 | Flood | — | — | — | — | — | County |
| 29 May 2019 | Flood | — | — | — | — | — | County |
| 29 May 2019 | Flood | — | — | — | — | — | County |
| 28 May 2019 | Flood | — | — | — | — | — | County |
| 1 May 2019 | Flood | — | — | — | — | — | County |
| 1 May 2019 | Flood | — | — | — | — | — | County |
| 1 May 2019 | Flood | — | — | — | — | — | County |
| 11 Apr 2019 | Flood | — | — | — | — | — | County |
| 1 Apr 2019 | Flood | — | — | — | — | — | County |
| 1 Apr 2019 | Flood | — | — | — | — | — | County |
| 1 Apr 2019 | Flood | — | — | — | — | — | County |
| 16 Mar 2019 | Flood | — | — | — | — | — | County |
| 15 Mar 2019 | Flood | — | — | — | — | — | County |
| 15 Mar 2019 | Flood | — | — | — | — | — | County |
| 14 Mar 2019 | Flood | — | — | — | — | — | County |
| 13 Mar 2019 | Flood | — | $1.2M | — | — | — | County |
| 13 Mar 2019 | Flood | — | — | — | — | — | County |
| 13 Mar 2019 | Flood | — | — | — | — | — | County |
| 13 Mar 2019 | Flood | — | — | — | — | — | County |
| 11 Oct 2018 | Flood | — | — | — | — | — | County |
| 10 Oct 2018 | Flood | — | — | — | — | — | County |
| 10 Oct 2018 | Flood | — | — | — | — | — | County |
| 1 Oct 2018 | Flood | — | — | — | — | — | County |
| 1 Oct 2018 | Flood | — | — | — | — | — | County |
| 23 Sep 2018 | Flood | — | — | — | — | — | County |
| 21 Sep 2018 | Flood | — | — | — | — | — | County |
| 20 Sep 2018 | Flash Flood | — | — | — | — | — | County |
| 20 Sep 2018 | Flood | — | — | — | — | — | County |
| 20 Sep 2018 | Flood | — | — | — | — | — | County |
| 20 Sep 2018 | Flood | — | — | — | — | — | County |
| 4 Sep 2018 | Flood | — | — | — | — | — | County |
| 1 Jul 2018 | Flood | — | — | — | — | — | County |
| 1 Jul 2018 | Flood | — | — | — | — | — | County |
| 1 Jul 2018 | Flood | — | — | — | — | — | County |
| 1 Jul 2018 | Flood | — | — | — | — | — | County |
| 24 Jun 2018 | Flood | — | — | — | — | — | County |
| 21 Jun 2018 | Flood | — | — | — | — | — | County |
| 21 Jun 2018 | Flood | — | — | — | — | — | County |
| 21 Jun 2018 | Flood | — | — | — | — | — | County |
| 21 Jun 2018 | Flood | — | — | — | — | — | County |
| 13 May 2018 | Flood | — | — | — | — | — | County |
| 12 May 2018 | Flood | — | — | — | — | — | County |
| 12 May 2018 | Flood | — | — | — | — | — | County |
| 1 May 2018 | Flood | — | — | — | — | — | County |
| 1 May 2018 | Flood | — | — | — | — | — | County |
| 21 Apr 2018 | Flood | — | — | — | — | — | County |
| 21 Apr 2018 | Flood | — | — | — | — | — | County |
| 1 Apr 2018 | Flood | — | — | — | — | — | County |
| 1 Apr 2018 | Flood | — | — | — | — | — | County |
| 29 Mar 2018 | Flood | — | — | — | — | — | County |
| 24 Mar 2018 | Flood | — | — | — | — | — | County |
| 8 Mar 2018 | Flood | — | — | — | — | — | County |
| 6 Mar 2018 | Flood | — | — | — | — | — | County |
| 1 May 2016 | Flood | — | — | — | — | — | County |
| 29 Apr 2016 | Flood | — | — | — | — | — | County |
| 6 Jun 2015 | Flash Flood | — | — | — | — | — | County |
| 16 Jun 2014 | Flood | — | $50K | — | — | — | County |
| 15 Jun 2014 | Flood | — | — | — | — | — | County |
| 15 Jun 2014 | Flood | — | $1.0M | $1.0M | — | — | County |
| 26 May 2013 | Flood | — | — | — | — | — | County |
| 28 May 2012 | Flood | — | — | — | — | — | County |
| 7 May 2012 | Flood | — | — | — | — | — | County |
| 1 Sep 2011 | Flood | — | — | — | — | — | County |
| 1 Aug 2011 | Flood | — | — | — | — | — | County |
| 1 Aug 2011 | Flood | — | — | — | — | — | County |
| 13 Jul 2011 | Flood | — | — | — | — | — | County |
| 1 Jul 2011 | Flood | — | — | — | — | — | County |
| 1 Jun 2011 | Flood | — | — | — | — | — | County |
| 1 Jun 2011 | Flood | — | — | — | — | — | County |
| 25 May 2011 | Flood | — | — | — | — | — | County |
| 22 May 2011 | Flood | — | — | — | — | — | County |
| 1 Apr 2011 | Flood | — | $100K | — | — | — | County |
| 17 Mar 2011 | Flood | — | — | — | — | — | County |
| 18 Feb 2011 | Flood | — | — | — | — | — | County |
| 1 Oct 2010 | Flood | — | — | — | — | — | County |
| 23 Sep 2010 | Flood | — | $100K | — | — | — | County |
| 1 Aug 2010 | Flood | — | — | — | — | — | County |
| 23 Jul 2010 | Flood | — | — | — | — | — | County |
| 22 Jun 2010 | Flash Flood | — | — | — | — | — | County |
| 13 Jun 2010 | Flood | — | — | — | — | — | County |
| 1 Apr 2010 | Flood | — | — | — | — | — | County |
| 12 Mar 2010 | Flood | — | — | — | — | — | County |
| 11 Feb 2009 | Flood | — | — | — | — | — | County |
| 20 Jul 2008 | Flash Flood | — | — | — | — | — | County |
| 5 Jun 2008 | Flood | — | — | — | — | — | County |
| 16 Jun 2007 | Flash Flood | — | — | — | — | — | County |
| 1 Apr 2007 | Flood | — | — | — | — | — | County |
| 12 Mar 2007 | Flood | — | — | — | — | — | County |
| 16 Jun 2006 | Flash Flood | — | — | — | — | — | County |
| 1 Apr 2006 | Flood | — | — | — | — | — | County |
| 20 Jun 2005 | Flash Flood | — | — | — | — | — | County |
| 4 Jun 2005 | Flash Flood | — | — | — | — | — | County |
| 21 Apr 2005 | Flash Flood | — | — | — | — | — | County |
| 16 Jun 2004 | Flash Flood | — | — | — | — | — | County |
| 1 Jun 2004 | Flood | — | — | — | — | — | Forecast zone |
| 31 May 2004 | Flood | — | — | — | — | — | Forecast zone |
| 9 May 2004 | Flash Flood | — | — | — | — | — | County |
| 7 Jun 2002 | Flash Flood | — | — | — | — | — | County |
| 28 May 2002 | Flash Flood | — | — | — | — | — | County |
| 1 Apr 2001 | Flood | — | — | — | — | — | Forecast zone |
| 13 Jun 2000 | Flash Flood | — | — | — | — | — | County |
| 17 May 2000 | Flash Flood | — | — | — | — | — | County |
| 20 Jul 1999 | Flash Flood | — | — | — | — | — | County |
| 5 Jun 1999 | Flash Flood | — | — | — | — | — | County |
| 5 Jun 1999 | Flash Flood | — | — | — | — | — | County |
| 1 May 1997 | Flood | — | — | — | — | — | Forecast zone |
| 1 Apr 1997 | Flood | — | — | — | — | — | Forecast zone |
| 12 Mar 1997 | Flood | — | — | — | — | — | Forecast zone |
Questions and answers
How many flood events has Union County had?
160 events in the NCEI Storm Events record between 1950 and 2026. Reporting of floods and flash floods became far more complete after 1996, so early decades undercount.
When was the last recorded flood event in Union County?
24 Jul 2025 (Flash Flood). Records reach NCEI about 120 days after the month ends.
What was the most damaging flood event recorded in Union County?
The flood of 21 Jun 2024, with property damage estimated by NCEI at $55M.
How does Union County compare with South Dakota for flood?
34.7 events per 100 square miles against 4.5 statewide; the county holds 160 of the state's 3,390 recorded events.
Provenance
NOAA NCEI Storm Events Database, yearly details files through 30 Jun 2026, public domain. County-recorded events plus zone-recorded events whose forecast zone is named for the county (marked "Forecast zone"). Population and area from the US Census Bureau (2021). Built 1 Oct 2026. See the methodology, the Flood hub and the county page.