Enter any address in Dewey County, South Dakota to see its FEMA flood zone
River overflow and flash flooding are the primary flood concerns in Dewey County. Recent events illustrate these risks, including flooding along the Bad River and Virgin Creek in September 2025 due to heavy rainfall and saturated soils. Additionally, snowmelt and ice jamming contributed to significant river flooding in March and April 2019, impacting the Grand, Moreau, and Bad rivers.
These events caused widespread flooding of roads, cropland, and affected homes and businesses. Residents living near the Grand, Moreau, and Bad rivers, as well as those in areas prone to flash flooding, should pay particular attention to flood risk.
Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.
7 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.
Dewey County, South Dakota has recorded 34 flood-related events since 1996 according to NOAA's Storm Events Database, including 14 flash floods and 20 river or area floods. The county has received 17 federal disaster declarations, 4 of which involved flooding or coastal storms. Enter any address above to check its FEMA flood zone designation.
FEMA Disaster Declarations (1976–2020)
Source: OpenFEMA Disaster Declarations Summaries.
| Declaration | Type | Date |
|---|---|---|
| Covid-19 | Biological | Jan 20, 2020 |
| Covid-19 Pandemic | Biological | Jan 20, 2020 |
| Severe Winter Storm, Snowstorm, And Flooding | Flood | Mar 13, 2019 |
| Severe Winter Storm | Severe Storm | Dec 24, 2016 |
| Severe Storms, Tornadoes, And Flooding | Flood | Jun 13, 2014 |
| Severe Winter Storm, Snowstorm, And Flooding | Severe Storm | Oct 3, 2013 |
| Severe Storms, Tornadoes, And Flooding | Severe Storm | Jun 16, 2010 |
| Severe Winter Storm | Severe Storm | Jan 20, 2010 |
| Severe Storms And Flooding | Severe Storm | Mar 11, 2009 |
| Severe Winter Storm And Record And Near Record Snow | Snowstorm | Nov 5, 2008 |
NOAA Storm Events Database (1996–2025)
Source: NOAA National Weather Service Storm Events Database.
| Type | Date | Damage |
|---|---|---|
| Flood | Sep 18, 2025 | 0.00K |
| Flood | Mar 26, 2019 | 0.00K |
| Flood | Mar 24, 2019 | 0.00K |
| Flood | May 1, 2019 | 0.00K |
| Flood | Jun 1, 2019 | 0.00K |
| Flood | Apr 1, 2019 | 198.80K |
| Flash Flood | Aug 12, 2017 | 0.00K |
| Flash Flood | Jul 22, 2016 | 0.00K |
| Flood | Jun 20, 2014 | 0.00K |
| Flood | Mar 11, 2014 | 0.00K |
Flood — Sep 18, 2025
Moderate to heavy rainfall occurred across a broad portion of Stanley and Dewey counties. The COOP observer 3 miles west southwest of Wendt would record a 2 day total of 4.94 while the CoCoRaHS observer in Fort Pierre received 4.06 over 3 days. This area had also received about an inch of rainfall on or around the 15th. Rainfall and saturated soils resulted in flooding of several streams and cr...
Flood — Mar 26, 2019
Much above normal winter snowfall and melt water/ice jams along with heavy rains in the middle of March brought flooding across parts of central and northeast South Dakota for late March. Rivers and creeks flooded across much of the area along with many fields and roads. The flooding damaged many of the roads and culverts across the region. Some structures were also flooded. Lake levels also ro...
Flood — Mar 24, 2019
Much above normal snow pack melt water and ice jamming brought flooding on the the Grand, Moreau, and Bad rivers across Corson, Dewey, Jones, and Stanley counties at the end of March. The Grand River at Little Eagle rose to moderate flood stage, nearly 4 and half feet above the flood stage of 15 feet. The Moreau River near Whitehorse rose to major flood stage, almost 28 feet or 7 feet above flo...
Flood — May 1, 2019
March and April snowmelt and heavy rain flooding along with above normal May precipitation resulted in hundreds of thousands of acres of crops damaged or delayed/unplanted across central and northeast South Dakota. The widespread flooding continued into June with millions of dollars of loss.
Flood — Jun 1, 2019
Spring snowmelt and heavy rain flooding from March, April, and May continued into June. This combined with above normal June rainfall resulted in hundreds of thousands of acres of crops damaged or unplanted across central and northeast South Dakota. For the entire state of South Dakota, nearly 4 million acres of crops were left unplanted as a result of the flooding. Total damaged or unplanted c...
Source: NOAA National Weather Service Storm Events Database.
FEMA assigns flood zone designations to areas in Dewey County, South Dakota:
AE High Risk — 1% annual chance of flooding. Insurance required.
VE Very High Risk — Coastal flooding with wave action.
X (Shaded) Moderate Risk — 500-year floodplain.
X Low Risk — Outside major floodplains.
Properties in Dewey County, South Dakota that are in FEMA-designated Special Flood Hazard Areas (zones A and V) with federally backed mortgages are required to carry flood insurance.
Even outside high-risk zones, flood insurance is recommended. From 2014 to 2024, nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area.
Visit FloodSmart.gov to find an agent and get a quote.