Custer County, Idaho: Natural Disaster Risk and History
Custer County, Idaho has a Relatively Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 52.4 out of 100, higher than about 52% of US counties, with landslides, avalanches and wildfires scoring highest of its 18 hazards and $11 million a year in expected losses.
OpenFEMA lists 5 federal disaster declarations that included Custer County since 1983, not counting 2 for COVID-19; the latest is DR-4333-ID (Flooding, Landslides, and Mudslides, declared 27 August 2017). NOAA's Storm Prediction Center recorded 2 tornadoes touching Custer County from 1950 to 2025.
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Population 4,271 Buildings worth $2.3 billion Area 4,989 sq mi Risk rank in Idaho 13 of 44 FIPS 16037
All 18 hazards, highest risk first
FEMA National Risk Index| Hazard | Risk rating | Score | Expected loss a year | How often | Events in record |
|---|---|---|---|---|---|
| Landslide | Relatively High | 98.2 | $413,916 | about 7.3 a year | — |
| Avalanche | Very High | 96.8 | $3.0 million | about once every 4.3 years | 7 |
| Wildfire | Relatively Low | 87.0 | $543,687 | about once every 794 years | — |
| Earthquake | Relatively Low | 79.3 | $950,700 | about once every 36 years | — |
| Inland flooding | Relatively Low | 57.3 | $5.1 million | about once every 1.8 years | 16 |
| Winter weather | Relatively Low | 50.4 | $39,984 | about 2 a year | 385 |
| Lightning | Relatively Low | 43.7 | $115,103 | about 28 a year | 38,498 strikes |
| Cold wave | Relatively Low | 30.4 | $266,439 | about once every 1.2 years | 16 |
| Volcanic activity | Very Low | 29.6 | $1 | rarer than once in 1,000 years | 5 |
| Heat wave | Very Low | 20.5 | $39,827 | about once every 3.3 years | 5.6 |
| Strong wind | Very Low | 15.7 | $82,146 | about once every 4.0 years | 10 |
| Drought | Very Low | 15.0 | $387 | about 94 a year | 2,373 |
| Ice storm | Very Low | 7.7 | $2,360 | about once every 67 years | 0 |
| Tornado | Very Low | 3.0 | $4,151 | about once every 7.5 years | 3 |
| Hail | Very Low | 2.1 | $1,830 | about once every 13 years | 2.9 |
| Coastal flooding | Not Applicable | — | — | — | — |
| Hurricane | Not Applicable | — | — | — | — |
| Tsunami | Not Applicable | — | — | — | — |
Score: FEMA's percentile among US counties that face the hazard (higher = more risk). Expected loss: FEMA's modelled average yearly loss to buildings, people (as a statistical value) and crops. How often: FEMA's annualised frequency of the hazard in the county; for some hazards it counts event-days, so it is a rough guide, not a forecast. "Not Applicable" means FEMA does not model that hazard here.
Federal disaster declarations 5
Most common: Flood 1, Hurricane 1, Fire 1, Severe Storm 1.
| Decade | Declarations | Incident types |
|---|---|---|
| 1980s | 1 | Earthquake |
| 1990s | 1 | Severe Storm |
| 2000s | 2 | Hurricane, Fire |
| 2010s | 1 | Flood |
The last 5
Widest declarations that included Custer County
- Hurricane Katrina (2005, EM-3244-ID): 44 Idaho counties designated.
- Wildfires (2000, DR-1341-ID): 15 Idaho counties designated.
- Severe Storms, Snowmelt, Land/Mud Slides, Flooding (1997, DR-1177-ID): 12 Idaho counties designated.
Named storms in its declarations: Hurricane Katrina (2005).
Not counted above: 2 COVID-19 ("Biological") declarations — in 2020 every US county was included. Idaho also had 8 statewide declarations with no county list.
Tornado record since 1950 2
| Tornadoes touching the county | 2 |
|---|---|
| Strongest-rated | (E)F0 ×2 |
| Peak month | April (1) |
| Deadliest | — |
| Longest path | 24 Apr 2008, EF0, 0.1 mi path |
| Most recent | 20 Aug 2014, EF0, 0.1 mi path |
| Deaths / injuries on those paths | 0 / 0 |
| Rating | (E)F0 | (E)F1 | (E)F2 | (E)F3 | (E)F4 | (E)F5 | Unrated |
|---|---|---|---|---|---|---|---|
| Count | 2 | 0 | 0 | 0 | 0 | 0 | 0 |
| Decade | 1950s | 1960s | 1970s | 1980s | 1990s | 2000s | 2010s | 2020s |
|---|---|---|---|---|---|---|---|---|
| Count | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 |
Deaths and injuries are for each tornado's whole path, which can run beyond this county. F-scale ratings before February 2007, Enhanced Fujita (EF) after.
How Custer County compares with its 5 nearest counties
| County | Distance | Overall risk | Score | Top hazard |
|---|---|---|---|---|
| Custer County (this page) | — | Relatively Low | 52.4 | Landslide |
| Lemhi County | 83 km | Very Low | 41.4 | Landslide |
| Blaine County | 95 km | Relatively Low | 65.4 | Avalanche |
| Camas County | 96 km | Very Low | 6.0 | Avalanche |
| Butte County | 106 km | Very Low | 4.4 | Avalanche |
| Valley County | 117 km | Relatively Low | 55.6 | Wildfire |
Nearest by distance between county centres. Every county in Idaho, ranked.
Vulnerability and resilience
| Social vulnerability | Very High 91.6 |
|---|---|
| Community resilience | Very Low 10.0 |
| Community risk factor | 1.69 |
| Expected annual loss, all hazards | $11 million |
FEMA scales expected losses up where social vulnerability is high (people who may find it harder to prepare, evacuate or recover) and down where community resilience is high. A factor above 1 raises the risk score. For social vulnerability a high rating is worse; for resilience a high rating is better.
Prepare for Custer County's main hazards
- Right now: National Weather Service alerts for Idaho · all official warnings on Global Incident Tracker.
- Landslide: Landslides recorded
- Avalanche: Official warnings now
- Wildfire: US wildfires now · Wildfire smoke: what protects you
- Your property's flood zone: FEMA Flood Map Service Center ↗ — this page cannot tell you that.
- Official preparedness guidance: Ready.gov ↗ and your county emergency management office.
What this page shows, and what it misses
FEMA's National Risk Index rates a whole county against every other US county; it is a planning-level estimate for nationwide comparison, not a flood-zone map and not a substitute for a local risk assessment or the risk to one home. Declarations are presidential disaster, emergency and fire management declarations that named this county; state declarations and SBA or USDA designations are not included. Tornadoes are counted when the county is one of up to four listed on the track; 670 tornadoes that crossed a state line carry no county list in NOAA's file and are left out.
Federal Emergency Management Agency (FEMA), National Risk Index Dataset: National Risk Index Counties - v1.20.0 (December 2025). Retrieved from https://services.arcgis.com/XG15cJAlne2vxtgt/ArcGIS/rest/services/National_Risk_Index_Counties/FeatureServer/0/query on November 2, 2026, 1:20 PM EST. This product uses the Federal Emergency Management Agency’s National Risk Index dataset API or downloadable datasets but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
Federal Emergency Management Agency (FEMA), OpenFEMA Dataset: Disaster Declarations Summaries - v2, retrieved from https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries on November 2, 2026, 1:21 PM EST. This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
Tornado records: NOAA/NWS Storm Prediction Center, Severe Weather Database, tornadoes 1950–2025 (https://www.spc.noaa.gov/wcm/data/1950-2025_actual_tornadoes.csv, downloaded 2 November 2026). Public domain; not endorsed by NOAA. Compiled by Global Incident Tracker.
Questions about Custer County
What natural disasters is Custer County, Idaho most at risk from?
Custer County, Idaho has a Relatively Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 52.4 out of 100, higher than about 52% of US counties, with landslides, avalanches and wildfires scoring highest of its 18 hazards and $11 million a year in expected losses.
How many federal disaster declarations has Custer County had?
OpenFEMA lists 5 federal disaster declarations that included Custer County since 1983, not counting 2 for COVID-19; the latest is DR-4333-ID (Flooding, Landslides, and Mudslides, declared 27 August 2017). Another 8 Idaho declarations were made statewide without a county list.
How many tornadoes have hit Custer County?
NOAA's Storm Prediction Center recorded 2 tornadoes touching Custer County from 1950 to 2025.
Is the National Risk Index a flood zone map?
No. The National Risk Index is a planning-level estimate for a whole county, built for nationwide comparison. It does not tell you the flood zone or the risk of a single property: for that, look up the address on FEMA's Flood Map Service Center (msc.fema.gov) and ask your local floodplain manager.