1 flood insurance claims·$1,902 paid·1 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 Custer County, Idaho. 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.
Flash flooding from summer thunderstorms and spring snowmelt dominates the flood risk profile in Custer County. Over the last 30 years, the NOAA Storm Events Database has recorded 10 flash flood events and 8 general flood events in the area.
Recent history illustrates these seasonal hazards. In June 2023, heavy rainfall combined with snowmelt in the Salmon Challis National Forest, washing away Forest Service road 135 near the intersection of Bear Creek and Antelope Pass Roads. Earlier, in August 2021, a sustained push of monsoonal moisture brought repeated flooding episodes to the region.
Properties situated near mountain streams, forest roads, and areas susceptible to rapid runoff should pay the closest attention to these hazards. National Flood Insurance Program records indicate limited historical claims activity, with a single recorded claim in Zone X resulting in an average payout of $1,902 and an average recorded water depth of 0 inches.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
3 NOAA storm reports from Custer County describe what happened, in the words of the forecasters who covered it. Read the Idaho flood stories →
7 federal disaster declarations since 1983, 1 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Flooding, Landslides, And Mudslides | May 6, 2017 |
| Hurricane Katrina | Aug 29, 2005 |
| Wildfires | Jul 27, 2000 |
| Severe Storms, Snowmelt, Land/mud Slides, Flooding | Mar 14, 1997 |
| Earthquake | Oct 28, 1983 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
18 since 1996: 10 flash floods and 8 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Sep 9, 2025 | — |
| Flood | Jun 12, 2023 | $20,000 |
| Flash Flood | Aug 2, 2021 | — |
| Flash Flood | Aug 1, 2021 | — |
| Flood | Mar 13, 2018 | $65,000 |
| Flood | Jun 1, 2018 | $10,000 |
| Flood | Feb 5, 2017 | $195,000 |
| Flood | May 1, 2017 | $3.5M |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flash Flood · Sep 9, 2025. A mudslide occurred in Custer County on Bayhorse Creek Rd about 1 mile from the Bayhorse town site.
Flood · Jun 12, 2023. Forest Service road 135 washed away near the intersection of Bear Creek and Antelope Pass Roads. Rainfall combined with snow melt continued to create flooding in the Salmon Challis National Forest.
Flash Flood · Aug 2, 2021. Continued push of monsoonal moisture into Idaho caused continued flooding into the first couple of days of August.
Flash Flood · Aug 1, 2021. Continued push of monsoonal moisture into Idaho caused continued flooding into the first couple of days of August.
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 Custer 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.