1 flood insurance claims·$450 paid·3 federal flood & hurricane disasters
Share of the whole county outline, rivers and lakes included; parts FEMA hasn’t mapped count as zero.
Shaded areas are FEMA’s mapped flood hazard zones in and around Corson County, South Dakota. Zoomed out they are simplified; at street level the map switches to FEMA’s exact layer. Tap anywhere to check that spot, or search an address above.
River flooding dominates the flood character of Corson County, supported by 41 recorded flood events compared to 14 flash flood events over the last 30 years according to the NOAA Storm Events Database.
Recent events illustrate this river flood risk. In May 2025, seasonal rainfall totaling 4 to 6 inches—including 5.6 inches recorded 8 miles south-southwest of Keldron—caused the Grand River near Little Eagle to crest at 15.43 feet, which is 0.43 feet above flood stage, resulting in minor flooding of pastureland. Similarly, heavy rainfall ranging from 3.84 inches to 4.92 inches across eastern Corson County in June 2023 caused Oak Creek near Wakpala to reach minor flood stage.
Properties near rivers and low-lying agricultural areas should pay the most attention to flood risk, as historical events primarily impact river gauges and local pastureland. FEMA NFIP records show 1 claim in an unknown zone, with an average payout of $450 and an average recorded water depth of 0 inches.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
16 NOAA storm reports from Corson County describe what happened, in the words of the forecasters who covered it. Read the South Dakota flood stories →
27 federal disaster declarations since 1976, 3 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Storms, Tornadoes, And Flooding | Jun 13, 2014 |
| Severe Winter Storm, Snowstorm, And Flooding | Oct 3, 2013 |
| Severe Storms, Tornado, And Flooding | May 24, 2013 |
| Severe Winter Storm | Apr 2, 2010 |
| Severe Winter Storm | Jan 20, 2010 |
| Severe Storms And Flooding | Mar 11, 2009 |
| Severe Winter Storm And Record And Near Record Snow | Nov 5, 2008 |
| Hurricane Katrina Evacuation | Sep 6, 2005 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
55 since 1996: 14 flash floods and 41 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flood | May 20, 2025 | — |
| Flood | May 16, 2025 | — |
| Flood | Jun 25, 2023 | — |
| Flood | Apr 11, 2023 | — |
| Flood | May 12, 2022 | — |
| Flood | Jun 10, 2021 | — |
| Flash Flood | Jun 8, 2021 | — |
| Flood | Mar 7, 2020 | — |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flood · May 20, 2025. More seasonal rainfall was observed in middle to late May across north central South Dakota. A local area of moderate to heavy rain, between 4 to 6 inches, was observed with a system on May 15th and 16th, with the COOP observer located 8 miles south southwest of Keldron recording 5.6 inches of moisture. This would result in minor flooding of the Grand River, with the gauge near Little Eagle topping out at 15.43 fe…
Flood · May 16, 2025. More seasonal rainfall was observed in middle to late May across north central South Dakota. A local area of moderate to heavy rain, between 4 to 6 inches, was observed with a system on May 15th and 16th, with the COOP observer located 8 miles south southwest of Keldron recording 5.6 inches of moisture. This would result in minor flooding of the Grand River, with the gauge near Little Eagle topping out at 15.43 fe…
Flood · Jun 25, 2023. Several rounds of showers and thunderstorms across eastern Corson County from the afternoon of June 20th through the morning of the 23rd culminated with a widespread heavy rainfall event from the evening of the 23rd through the evening of the 24th. Some 5-day rainfall totals include 4.92 2 miles southwest of McLaughlin, 4.51 2 miles north-northwest of Mobridge, 3.85 at the Mobridge Municipal Airport, and 3.84 in T…
Flood · Apr 11, 2023. Snowmelt resulted in flooding along Oak Creek. Temperatures on April 11th hit a record 90 degrees in Mobridge after several days of mild weather and rapid snowmelt. The river gauge near Wakpala peaked at 15.92 feet early April 12th, just below major flood stage, though this mainly affected agricultural lands.
National Weather Service narratives, lightly trimmed. Source: NOAA Storm Events Database.
Every colour on the map above is a place on this drawing: where the ground sits relative to the flood FEMA plans for.
If a building in Corson County is in a high-risk zone (A or V) and its mortgage comes from a federally regulated or insured lender, or is federally backed, flood insurance is required.
Outside those zones it is optional, and often worth having: from 2014 to 2024 nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area. Since Risk Rating 2.0, NFIP premiums are set for each building, so the only reliable price is a quote: FloodSmart.gov or a local agent.