Bonneville County, Idaho: Natural Disaster Risk and History
Bonneville County, Idaho has a Relatively Moderate natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 82.4 out of 100, higher than about 82% of US counties, with earthquakes, avalanches and landslides scoring highest of its 18 hazards and $65 million a year in expected losses.
OpenFEMA lists 5 federal disaster declarations that included Bonneville County since 1964, not counting 2 for COVID-19; the latest is FM-5151-ID (Henrys Creek Fire, declared 25 August 2016). NOAA's Storm Prediction Center recorded 6 tornadoes touching Bonneville County from 1950 to 2025.
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Population 123,895 Buildings worth $29 billion Area 1,920 sq mi Risk rank in Idaho 2 of 44 FIPS 16019
All 18 hazards, highest risk first
FEMA National Risk Index| Hazard | Risk rating | Score | Expected loss a year | How often | Events in record |
|---|---|---|---|---|---|
| Earthquake | Relatively Moderate | 94.2 | $16 million | about once every 31 years | — |
| Avalanche | Relatively High | 94.2 | $3.8 million | about once every 3.7 years | 8 |
| Landslide | Relatively Moderate | 94.2 | $141,697 | about 1.5 a year | — |
| Cold wave | Relatively High | 93.0 | $12 million | about 1.4 a year | 27 |
| Wildfire | Relatively Moderate | 90.3 | $1.9 million | about once every 186 years | — |
| Lightning | Relatively High | 89.5 | $1.5 million | about 36 a year | 137,111 strikes |
| Hail | Relatively Moderate | 84.9 | $1.6 million | about once every 2.3 years | 17 |
| Heat wave | Relatively Moderate | 81.2 | $2.1 million | about once every 1.5 years | 9.7 |
| Inland flooding | Relatively Moderate | 78.6 | $24 million | about once every 1.6 years | 17 |
| Volcanic activity | Very Low | 72.3 | $163 | rarer than once in 1,000 years | 4 |
| Winter weather | Relatively Moderate | 66.2 | $149,512 | about 24 a year | 463 |
| Strong wind | Relatively Low | 43.9 | $611,735 | about once every 1.3 years | 29 |
| Ice storm | Very Low | 26.8 | $34,546 | about once every 67 years | 0 |
| Drought | Very Low | 19.4 | $4,696 | about 63 a year | 1,967 |
| Tornado | Very Low | 16.2 | $217,323 | about once every 5.6 years | 6 |
| 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 2, Fire 1, Hurricane 1, Severe Storm 1.
| Decade | Declarations | Incident types |
|---|---|---|
| 1960s | 1 | Flood |
| 1970s | 1 | Flood |
| 1990s | 1 | Severe Storm |
| 2000s | 1 | Hurricane |
| 2010s | 1 | Fire |
The last 5
Widest declarations that included Bonneville County
- Hurricane Katrina (2005, EM-3244-ID): 44 Idaho counties designated.
- Heavy Rains & Flooding (1964, DR-186-ID): 27 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 6
| Tornadoes touching the county | 6 |
|---|---|
| Strongest-rated | (E)F2 ×1 |
| Peak month | April (2) |
| Deadliest | 7 Apr 1978, F2, 1.5 mi path, 0 killed, 1 injured |
| Longest path | 14 Feb 2000, F1, 12 mi path |
| Most recent | 17 Nov 2017, EF0, 5 mi path |
| Deaths / injuries on those paths | 0 / 1 |
| Rating | (E)F0 | (E)F1 | (E)F2 | (E)F3 | (E)F4 | (E)F5 | Unrated |
|---|---|---|---|---|---|---|---|
| Count | 3 | 2 | 1 | 0 | 0 | 0 | 0 |
| Decade | 1950s | 1960s | 1970s | 1980s | 1990s | 2000s | 2010s | 2020s |
|---|---|---|---|---|---|---|---|---|
| Count | 0 | 0 | 1 | 2 | 1 | 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 Bonneville County compares with its 5 nearest counties
| County | Distance | Overall risk | Score | Top hazard |
|---|---|---|---|---|
| Bonneville County (this page) | — | Relatively Moderate | 82.4 | Earthquake |
| Madison County | 44 km | Relatively Low | 58.6 | Lightning |
| Teton County | 53 km | Very Low | 29.5 | Avalanche |
| Bingham County | 66 km | Relatively Low | 60.1 | Winter weather |
| Caribou County | 69 km | Very Low | 7.2 | Wildfire |
| Jefferson County | 74 km | Very Low | 40.1 | Winter weather |
Nearest by distance between county centres. Every county in Idaho, ranked.
Vulnerability and resilience
| Social vulnerability | Very Low 12.2 |
|---|---|
| Community resilience | Very High 92.4 |
| Community risk factor | 0.78 |
| Expected annual loss, all hazards | $65 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 Bonneville County's main hazards
- Right now: National Weather Service alerts for Idaho · all official warnings on Global Incident Tracker.
- Earthquake: Earthquakes today · Earthquake safety guide
- Avalanche: Official warnings now
- Landslide: Landslides recorded
- 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 Bonneville County
What natural disasters is Bonneville County, Idaho most at risk from?
Bonneville County, Idaho has a Relatively Moderate natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 82.4 out of 100, higher than about 82% of US counties, with earthquakes, avalanches and landslides scoring highest of its 18 hazards and $65 million a year in expected losses.
How many federal disaster declarations has Bonneville County had?
OpenFEMA lists 5 federal disaster declarations that included Bonneville County since 1964, not counting 2 for COVID-19; the latest is FM-5151-ID (Henrys Creek Fire, declared 25 August 2016). Another 8 Idaho declarations were made statewide without a county list.
How many tornadoes have hit Bonneville County?
NOAA's Storm Prediction Center recorded 6 tornadoes touching Bonneville County from 1950 to 2025. The deadliest: 7 Apr 1978, F2, 1.5 mi path, 0 killed, 1 injured (deaths and injuries are for the whole path).
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.