Enter any address in Custer County, South Dakota to see its FEMA flood zone
Flash flooding from thunderstorms is the dominant flood character in Custer County. Over the last 30 years, NOAA Storm Events data shows 21 flash flood events and 20 flood events. For example, in September 2023, a slow-moving thunderstorm produced 2 to 5 inches of rainfall in less than two hours, causing roads to be inundated with water and debris. In June 2020, a severe thunderstorm over the Custer area produced heavy rain and hail, leading to flash flooding on the east side of town.
National Flood Insurance Program (NFIP) claims data indicates that properties in Zone A have experienced the most claims, with an average payout of $11,768 and an average water depth of 4.8 feet. While fewer claims have been filed in Zone X_SHADED, the average water depth was recorded at 5.0 feet. Homeowners in Zone A and Zone X_SHADED should pay the most attention to flood risk.
Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.
12 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.
Custer County, South Dakota has recorded 41 flood-related events since 1996 according to NOAA's Storm Events Database, including 21 flash floods and 20 river or area floods. The county has received 16 federal disaster declarations, 5 of which involved flooding or coastal storms. Enter any address above to check its FEMA flood zone designation.
FEMA Disaster Declarations (1972–2026)
Source: OpenFEMA Disaster Declarations Summaries.
| Declaration | Type | Date |
|---|---|---|
| Qury Fire | Fire | Mar 12, 2026 |
| Covid-19 | Biological | Jan 20, 2020 |
| Covid-19 Pandemic | Biological | Jan 20, 2020 |
| Severe Storms And Flooding | Flood | May 21, 2019 |
| Legion Lake Fire | Fire | Dec 12, 2017 |
| Severe Winter Storm, Snowstorm, And Flooding | Severe Storm | Oct 3, 2013 |
| Myrtle Fire | Fire | Jul 19, 2012 |
| Hurricane Katrina Evacuation | Coastal Storm | Sep 6, 2005 |
| Sd - Battle Creek Fire - 08/18/02 | Fire | Aug 16, 2002 |
| Sd - Elk Mountain Fire Complex - 08/01/01 | Fire | Jul 30, 2001 |
NOAA Storm Events Database (1996–2025)
Source: NOAA National Weather Service Storm Events Database.
| Type | Date | Damage |
|---|---|---|
| Flood | Sep 13, 2023 | 0.00K |
| Flash Flood | Sep 13, 2023 | 0.00K |
| Flash Flood | Aug 24, 2022 | 20.00K |
| Flash Flood | Jun 25, 2020 | 0.00K |
| Flood | May 28, 2019 | 100.00K |
| Flood | May 21, 2019 | 100.00K |
| Flood | Jul 3, 2019 | 0.00K |
| Flood | Aug 2, 2019 | 0.00K |
| Flash Flood | Aug 2, 2019 | 1.00M |
| Flood | Jul 18, 2018 | 0.00K |
Flood — Sep 13, 2023
A slow-moving thunderstorm briefly became severe over central Pennington County into north central Custer County, producing hail up to golf ball size along with heavy rainfall. The storm became nearly stationary just west of Hermosa and produced 2 to 5 inches of rainfall in less than 2 hours. Runoff from the heavy rainfall caused several roads to be inundated with water and debris west of Hermosa.
Flash Flood — Sep 13, 2023
A slow-moving thunderstorm briefly became severe over central Pennington County into north central Custer County, producing hail up to golf ball size along with heavy rainfall. The storm became nearly stationary just west of Hermosa and produced 2 to 5 inches of rainfall in less than 2 hours. Runoff from the heavy rainfall caused several roads to be inundated with water and debris west of Hermosa.
Flash Flood — Aug 24, 2022
A supercell thunderstorm developed over the southern Black Hills and tracked southeast, weakening on the adjacent plains. The storm produced large hail and heavy rain over the area. Other strong thunderstorms produced heavy rain and localized flash flooding over far southwestern South Dakota. Rain amounts of three to four inches were estimated in some areas. In Oglala Lakota County, flash flood...
Flash Flood — Jun 25, 2020
A severe thunderstorm developed in the Custer area and remained nearly stationary for close to an hour and a half. The storm produced a lot of hail around quarter size, which accumulated six inches deep in some areas. The large amounts of hail and heavy rain also caused flash flooding on the east side of Custer.
Flood — May 28, 2019
Several days of heavy rain, along with major to record flooding the previous week, led to more flooding across portions of the western South Dakota plains and foothills of the Black Hills. The period of wet weather culminated with heavy rain and thunderstorms over the Rapid City area during the afternoon and evening of May 31, which led to widespread flooded roads.
Source: NOAA National Weather Service Storm Events Database.
Source: OpenFEMA NFIP Individual Claims (2.25M records analyzed).
FEMA assigns flood zone designations to areas in Custer 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 Custer 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.