Boise County, Idaho
Natural disaster risk, federal disaster history and flood insurance facts.
Boise County, Idaho has a relatively low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is lower than 51% of US counties. It ranks 15th of 44 counties in Idaho. The costliest hazards here are wildfires, inland flooding and avalanches. FEMA estimates about $16 million a year in expected losses, or roughly $2,116 per resident. Since 1964 it has been included in 5 federal disaster or emergency declarations for natural events (3 major disasters). The most recent was in September 2012 (Karney Fire). Only 24 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 Boise County
- Clear dry plants and debris within 5 feet of the house.
- Get home insurance quotes early; availability varies by area.
- 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.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Wildfire | 97.2 | $8M | ||
| Inland flooding | 42.9 | $6M | ||
| Avalanche | 87.6 | $1M | ||
| Landslide | 97.3 | $356K | ||
| Strong wind | 23.6 | $225K | ||
| Earthquake | 40.0 | $158K | ||
| Winter weather | 51.9 | $70K | ||
| Heat wave | 14.9 | $36K | ||
| Lightning | 9.3 | $32K | ||
| Tornado | 4.0 | $13K | ||
| Cold wave | 4.6 | $13K | ||
| Hail | 4.5 | $11K | ||
| Ice storm | 13.2 | $8K | ||
| Volcanic activity | 31.9 | $3 | ||
| Drought | 12.4 | $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 relatively low 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 Boise 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 1961
Tornado risk by county ›The National Weather Service has logged 99 storm reports in Boise County since 1961, with 1 death and 6 injuries and about $8.3 million in reported damage. No tornadoes are on record here.
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| Aug 6, 2014 | Flood | Idaho City | $8M |
| Jul 22, 2008 | Flash Flood | Lowman | $100K |
| May 7, 2017 | Flood | Garden Vly | $100K |
| May 3, 1993 | Thunderstorm Wind | – | $50K |
| Oct 16, 2012 | Thunderstorm Wind | Garden Vly Arpt | $1K |
| Aug 21, 2010 | Thunderstorm Wind | Idaho City | 1 killed |
Source: NOAA Storm Events Database, county-based reports through Oct 25, 2025. 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 Boise 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 Boise 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; 5,689 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 |
|---|---|---|
| Ada County | 4 | |
| Elmore County | 9 | |
| Gem County | 5 | |
| Valley County | 10 | |
| Custer County | 5 |
Common questions about Boise County
What is the biggest natural hazard in Boise County?
Wildfire has the highest expected yearly losses in Boise County, about $8.2 million a year in FEMA's estimate. Inland flooding is second at $5.5 million.
How many federal disasters has Boise County had?
Boise County has been included in 5 federal disaster or emergency declarations for natural events since 1964, including 3 major disasters. The most recent was Karney Fire in September 2012.
Is Boise County a high-risk place to live?
Its overall rating is Relatively Low, 15th 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 Boise County?
Standard home insurance does not cover flooding. About 1 in 250 homes in Boise 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 Boise County had?
NOAA records list 0 tornadoes in Boise County since 1950. The weather service has also logged 21 hail reports and 26 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.