Boise County, Idaho: Natural Disaster Risk and History
Boise County, Idaho has a Relatively Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 48.9 out of 100, higher than about 48% of US counties, with landslides, wildfires and avalanches scoring highest of its 18 hazards and $16 million a year in expected losses.
OpenFEMA lists 5 federal disaster declarations that included Boise County since 1964, not counting 2 for COVID-19; the latest is FM-5019-ID (Karney Fire, declared 18 September 2012). NOAA's Storm Prediction Center has no tornado on record touching Boise County from 1950 to 2025.
Live weather alerts for Idaho All official warnings Latest FEMA declarations
Population 7,582 Buildings worth $2.2 billion Area 1,926 sq mi Risk rank in Idaho 15 of 44 FIPS 16015
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 Moderate | 97.3 | $355,989 | about 2.1 a year | — |
| Wildfire | Relatively Moderate | 97.2 | $8.2 million | about once every 57 years | — |
| Avalanche | Relatively High | 87.6 | $1.4 million | about once every 10 years | 3 |
| Winter weather | Relatively Low | 51.9 | $70,416 | about 18 a year | 336 |
| Inland flooding | Relatively Low | 42.9 | $5.5 million | about once every 1.2 years | 23 |
| Earthquake | Very Low | 40.0 | $158,284 | about once every 97 years | — |
| Volcanic activity | Very Low | 31.9 | $3 | rarer than once in 1,000 years | 2 |
| Strong wind | Relatively Low | 23.6 | $224,636 | about once every 3.4 years | 12 |
| Heat wave | Very Low | 14.9 | $36,261 | about 1.5 a year | 21 |
| Ice storm | Very Low | 13.2 | $7,751 | about once every 24 years | 3 |
| Drought | Very Low | 12.4 | $1 | about 7.8 a year | 357 |
| Lightning | Very Low | 9.3 | $31,686 | about 23 a year | 40,564 strikes |
| Cold wave | Very Low | 4.6 | $12,928 | about once every 19 years | 1 |
| Hail | Very Low | 4.5 | $10,597 | about once every 5.1 years | 7.5 |
| Tornado | Very Low | 4.0 | $13,132 | about once every 12 years | 0 |
| 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: Fire 2, Hurricane 1, Severe Storm 1, Flood 1.
| Decade | Declarations | Incident types |
|---|---|---|
| 1960s | 1 | Flood |
| 1990s | 1 | Severe Storm |
| 2000s | 2 | Hurricane, Fire |
| 2010s | 1 | Fire |
The last 5
Widest declarations that included Boise County
- Hurricane Katrina (2005, EM-3244-ID): 44 Idaho counties designated.
- Heavy Rains & Flooding (1964, DR-186-ID): 27 Idaho counties designated.
- Severe Storms, Flooding, Mud and Landslides (1997, DR-1154-ID): 18 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 0
No tornado in NOAA's Storm Prediction Center record touched Boise County between 1950 and 2025. That does not mean one cannot happen.
How Boise County compares with its 5 nearest counties
| County | Distance | Overall risk | Score | Top hazard |
|---|---|---|---|---|
| Boise County (this page) | — | Relatively Low | 48.9 | Landslide |
| Gem County | 54 km | Very Low | 34.4 | Wildfire |
| Ada County | 73 km | Relatively Moderate | 87.8 | Winter weather |
| Elmore County | 74 km | Relatively Low | 52.0 | Wildfire |
| Payette County | 82 km | Very Low | 17.1 | Wildfire |
| Valley County | 88 km | Relatively Low | 55.6 | Wildfire |
Nearest by distance between county centres. Every county in Idaho, ranked.
Vulnerability and resilience
| Social vulnerability | Relatively Low 33.3 |
|---|---|
| Community resilience | Very Low 13.2 |
| Community risk factor | 1.02 |
| Expected annual loss, all hazards | $16 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 Boise County's main hazards
- Right now: National Weather Service alerts for Idaho · all official warnings on Global Incident Tracker.
- Landslide: Landslides recorded
- Wildfire: US wildfires now · Wildfire smoke: what protects you
- Avalanche: Official warnings now
- 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 Boise County
What natural disasters is Boise County, Idaho most at risk from?
Boise County, Idaho has a Relatively Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 48.9 out of 100, higher than about 48% of US counties, with landslides, wildfires and avalanches scoring highest of its 18 hazards and $16 million a year in expected losses.
How many federal disaster declarations has Boise County had?
OpenFEMA lists 5 federal disaster declarations that included Boise County since 1964, not counting 2 for COVID-19; the latest is FM-5019-ID (Karney Fire, declared 18 September 2012). Another 8 Idaho declarations were made statewide without a county list.
How many tornadoes have hit Boise County?
NOAA's Storm Prediction Center has no tornado on record touching Boise 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.