Custer County, Idaho
Natural disaster risk, federal disaster history and flood insurance facts.
Custer County, Idaho has a relatively low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is higher than 52% of US counties. It ranks 13th of 44 counties in Idaho. The costliest hazards here are inland flooding, avalanches and earthquakes. FEMA estimates about $11 million a year in expected losses, or roughly $2,485 per resident. Since 1983 it has been included in 5 federal disaster or emergency declarations for natural events (4 major disasters). The most recent was in August 2017 (flooding, landslides and mudslides). Only 17 homes here carry federal flood insurance.
FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.
Top risks in Custer County
- Check the FEMA flood map for your address, and ask the seller or landlord about past flooding.
- Price a flood policy now. Most new federal policies take 30 days to start.
- Check avalanche forecasts before backcountry trips.
- Ask about slide paths near mountain homes.
- Ask whether an older house is bolted to its foundation.
- Consider separate earthquake insurance where risk is high.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Inland flooding | 57.3 | $5M | ||
| Avalanche | 96.8 | $3M | ||
| Earthquake | 79.3 | $951K | ||
| Wildfire | 87.0 | $544K | ||
| Landslide | 98.2 | $414K | ||
| Cold wave | 30.4 | $266K | ||
| Lightning | 43.7 | $115K | ||
| Strong wind | 15.7 | $82K | ||
| Winter weather | 50.4 | $40K | ||
| Heat wave | 20.5 | $40K | ||
| Tornado | 3.0 | $4K | ||
| Ice storm | 7.7 | $2K | ||
| Hail | 2.1 | $2K | ||
| Drought | 15.0 | $387 | ||
| Volcanic activity | 29.6 | $1 |
Scores are percentiles: a score of 90 means higher risk than about 90% of US counties for that hazard. Hazards FEMA does not rate here are left out. Social vulnerability is very high and community resilience is very low in FEMA's measures.
Federal disaster history
Recent disasters nationwide ›Declarations by decade
Federal declarations for natural events that included Custer County. 2020s bar runs to November 2026.
By type
Most recent
Idaho also had 16 statewide declarations that did not name single counties.
Storm history since 1962
Tornado risk by county ›The National Weather Service has logged 74 storm reports in Custer County since 1962, with 0 deaths and 3 injuries and about $8.4 million in reported damage. The strongest on record here was an EF0 tornado on April 24, 2008 near Challis.
Strongest tornadoes
| Date | Strength | Near | Hurt / killed |
|---|---|---|---|
| Apr 24, 2008 | EF0 | Challis | 0 / 0 |
| Aug 20, 2014 | EF0 | Mackay | 0 / 0 |
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| May 1, 2017 | Flood | Stanley | $4M |
| Aug 1, 2014 | Heavy Rain | Sunbeam | $3M |
| Jun 1, 2017 | Flood | Stanley | $900K |
| Jul 3, 2008 | Thunderstorm Wind | Stanley | $420K |
| Feb 5, 2017 | Flood | Stanley | $195K |
| Mar 1, 2017 | Flood | Stanley | $90K |
Source: NOAA Storm Events Database, county-based reports through Jul 22, 2026. Tornado records start in 1950, hail and wind in 1955, and floods and other storm types in 1996, so older decades undercount. Damage is in dollars of the year it happened and is often an estimate. Winter storms, heat and hurricanes are logged by forecast zone, not county, so they are not counted here.
Flood insurance in Custer County
Check your address flood zone ›National Flood Insurance Program (NFIP) records only; private flood policies are not included. Home counts as of Aug 3, 2026. Since 2021 NFIP prices each home separately under Risk Rating 2.0, so your price depends on the building, not the county. Ask an agent for a quote.
Homes in Custer County
Older homes and mobile homes usually suffer more damage in storms, floods and earthquakes, and can cost more to insure. If you are buying, ask about roof age, foundation bolting and any retrofits. Source: US Census Bureau, American Community Survey 2020 to 2024 5-year estimates; 3,137 housing units.
Compare in Idaho
All 44 ›| Largest counties | Overall risk | Top hazard |
|---|---|---|
| Ada County | Inland flooding | |
| Canyon County | Inland flooding | |
| Kootenai County | Inland flooding | |
| Bonneville County | Inland flooding | |
| Twin Falls County | Inland flooding | |
| Bannock County | Wildfire | |
| Madison County | Inland flooding | |
| Bingham County | Inland flooding |
Neighboring counties
| County | Overall risk | Declarations |
|---|---|---|
| Elmore County | 9 | |
| Blaine County | 8 | |
| Valley County | 10 | |
| Lemhi County | 3 | |
| Boise County | 5 | |
| Butte County | 4 |
Common questions about Custer County
What is the biggest natural hazard in Custer County?
Inland flooding has the highest expected yearly losses in Custer County, about $5.1 million a year in FEMA's estimate. Avalanche is second at $3 million.
How many federal disasters has Custer County had?
Custer County has been included in 5 federal disaster or emergency declarations for natural events since 1983, including 4 major disasters. The most recent was Flooding, Landslides, and Mudslides in August 2017.
Is Custer County a high-risk place to live?
Its overall rating is Relatively Low, 13th highest of 44 in Idaho. A county rating covers the whole area. Risk at one address can be much higher or lower, so check the FEMA flood map and ask about the home's history.
Do I need flood insurance in Custer County?
Standard home insurance does not cover flooding. About 1 in 250 homes in Custer County has federal flood insurance. Lenders require it in mapped high-risk zones, but many flood claims come from outside those zones.
How many tornadoes has Custer County had?
NOAA records list 2 tornadoes in Custer County since 1950. The strongest was an EF0 tornado on April 24, 2008 near Challis. The weather service has also logged 11 hail reports and 19 floods here.
Sources: FEMA National Risk Index (December 2025), OpenFEMA Disaster Declarations Summaries, and NFIP policy and claims data. Hazard Compass is independent and not affiliated with FEMA. These figures describe the whole county, not a single property, and are not insurance or safety advice. Report a problem.