257 flood insurance claims·$4.0M paid·10 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 Day 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.
Standard river and general flood events dominate Day County, accounting for 25 of the 39 recorded flood events over the last 30 years, alongside 11 flash floods and 3 lakeshore floods. Heavy precipitation and melting snow drive these occurrences. For instance, an unusually deep snowpack of 15 to 30 plus inches led to flooding in April 2023 following abnormally warm spring conditions. Later, severe storms on August 13-14, 2025, brought heavy rainfall, high winds, and hail that damaged siding and crops near Pierpont and downed trees in Roslyn.
NFIP claim records indicate that property owners across multiple zones face financial risk from these events. Zone X accounts for the highest claim volume with 131 claims averaging $15,929 and an average recorded water depth of 4 inches. Meanwhile, Zone A properties recorded 87 claims with an average payout of $27,700 and an average water depth of 1 inch. Properties in unshaded Zone X and areas with unknown designations also show significant historical payouts, averaging $26,705 and $13,149 respectively. Homeowners, real estate agents, and journalists should pay the closest attention to properties in both mapped high-risk zones and moderate-risk Zone X areas, as both experience frequent claims and documented water accumulation.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
15% of Day County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
102 NFIP claims with a recorded rated flood zone, 1978 to date. The zone is the one FEMA used to rate that policy, which may not match today’s map. Source: OpenFEMA NFIP claims.
In flood insurance claims here that reported a flood depth, the average was 2 inches.
Drawn to scale against an 80-inch door. Even a few inches soaks flooring, the bottom of the drywall and anything plugged in near the floor.
Average of the depths reported on claims (zero and implausible values left out); FEMA’s record doesn’t say exactly where each depth was measured. Source: OpenFEMA NFIP claims.
The worst year was 1999, with 82 claims and $1.1M paid.
Bar height is scaled by square root so ordinary years stay visible next to the worst one. NFIP claims by year of loss. Source: OpenFEMA.
12 NOAA storm reports from Day County describe what happened, in the words of the forecasters who covered it. Read the South Dakota flood stories →
24 federal disaster declarations since 1976, 10 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Flooding | Apr 9, 2023 |
| Severe Winter Storms And Snowstorm | Dec 12, 2022 |
| Severe Storm, Straight-line Winds, Tornadoes, And Flooding | May 12, 2022 |
| Severe Storms, Tornadoes, And Flooding | Sep 9, 2019 |
| Severe Winter Storm, Snowstorm, And Flooding | Mar 13, 2019 |
| Severe Winter Storm | Dec 24, 2016 |
| Flooding | Mar 11, 2011 |
| Flooding | Mar 10, 2010 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
39 since 1996: 11 flash floods, 25 river or area floods and 3 coastal floods or surges.
| Event | Date | Damage |
|---|---|---|
| Flood | Jun 26, 2025 | — |
| Flood | Aug 17, 2025 | — |
| Flood | Aug 13, 2025 | — |
| Flood | Apr 12, 2023 | $150,000 |
| Flood | Mar 27, 2019 | — |
| Flood | Aug 2, 2019 | — |
| Flood | May 1, 2019 | — |
| Flood | Jun 1, 2019 | — |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flood · Jun 26, 2025. On June 25th, multiple thunderstorms from the morning into the early afternoon caused flooding in parts of northeast South Dakota. A CoCoRaHS observer 4 miles south-southeast of Milbank recorded 3.33 inches of rain, while the COOP observer in Milbank measured 3.25 inches. Grant County Emergency Management sent photos of washed-out roads, and a resident near Ortley documented water reaching a home's foundation.||Th…
Flood · Aug 17, 2025. Brief but intense heavy rainfall from thunderstorms, on top of weeks of wet weather, resulted in additional flooding across Marshall, Hamlin, Codington, and Deuel counties starting on the 17th and persisting well into the 18th. An estimated 3 inches of rain fell in Lake Poinsett, while 1.63 inches was recorded by the COOP sensor 20 miles north northeast of Aberdeen, 1.62 inches was submitted by the CoCoRaHS volun…
Flood · Aug 13, 2025. Two clusters of storms would move across the forecast area on the 13th into the early morning hours of the 14th. The day started with an isolated stronger storm generating 1 inch hail 6 miles north northeast of Lowry. That cluster would continue to move east and intensify, with 1.5 inch hail observed 8 miles east of Pierpont. These storms would damage siding and crops around Pierpont, with additional thunderstorm…
Flood · Apr 12, 2023. The snowfall during the season in northeast and central South Dakota exceeded normal levels, with many locations ranking among the top 10 for the snowiest seasons. Additionally, the late spring conditions were unusually cold, resulting in a persistent and exceptionally deep snowpack until early April. The depth of the snowpack ranged from 15 to 30 plus inches, containing approximately 4 to 8 inches of snow water e…
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 Day 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.