Lewis County, Idaho
Natural disaster risk, federal disaster history and flood insurance facts.
Lewis County, Idaho has a very low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is lower than 97% of US counties. It ranks 42nd of 44 counties in Idaho. The costliest hazards here are inland flooding, wildfires and cold waves. FEMA estimates about $2.0 million a year in expected losses, or roughly $581 per resident. Since 1964 it has been included in 10 federal disaster or emergency declarations for natural events (8 major disasters). The most recent was in April 2026 (straight-line winds). Only 16 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 Lewis 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.
- Clear dry plants and debris within 5 feet of the house.
- Get home insurance quotes early; availability varies by area.
- Insulate pipes in outside walls, crawl spaces and garages.
- Know how to shut off the main water valve.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Inland flooding | 12.0 | $1M | ||
| Wildfire | 85.9 | $628K | ||
| Cold wave | 9.5 | $56K | ||
| Heat wave | 19.3 | $47K | ||
| Earthquake | 23.4 | $31K | ||
| Hail | 8.6 | $20K | ||
| Strong wind | 2.7 | $11K | ||
| Lightning | 2.2 | $6K | ||
| Tornado | 2.8 | $5K | ||
| Avalanche | 62.7 | $2K | ||
| Winter weather | 2.8 | $1K | ||
| Drought | 15.3 | $608 | ||
| Landslide | 39.5 | $519 | ||
| Ice storm | 1.2 | $419 |
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 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 Lewis 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 1970
Tornado risk by county ›The National Weather Service has logged 53 storm reports in Lewis County since 1970 and about $574,000 in reported damage. The strongest on record here was an EF0 tornado on October 7, 2010 near Harris Siding.
Strongest tornadoes
| Date | Strength | Near | Hurt / killed |
|---|---|---|---|
| Oct 7, 2010 | EF0 | Harris Siding | 0 / 0 |
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| Apr 14, 2024 | Debris Flow | Kamiah | $200K |
| Apr 9, 2019 | Flood | Kamiah | $100K |
| Aug 11, 2022 | Hail | Forest | $100K |
| Aug 29, 2017 | Thunderstorm Wind | Kamiah | $50K |
| Jun 2, 2010 | Heavy Rain | Kamiah | $32K |
| Aug 30, 2017 | Thunderstorm Wind | Nezperce | $20K |
Source: NOAA Storm Events Database, county-based reports through Jul 16, 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 Lewis 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 Lewis 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; 1,826 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 |
|---|---|---|
| Nez Perce County | 13 | |
| Idaho County | 16 | |
| Clearwater County | 13 |
Common questions about Lewis County
What is the biggest natural hazard in Lewis County?
Inland flooding has the highest expected yearly losses in Lewis County, about $1.2 million a year in FEMA's estimate. Wildfire is second at $627,585.
How many federal disasters has Lewis County had?
Lewis County has been included in 10 federal disaster or emergency declarations for natural events since 1964, including 8 major disasters. The most recent was Straight-Line Winds in April 2026.
Is Lewis County a high-risk place to live?
Its overall rating is Very Low, 42nd 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 Lewis County?
Standard home insurance does not cover flooding. About 1 in 111 homes in Lewis 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 Lewis County had?
NOAA records list 1 tornadoes in Lewis County since 1950. The strongest was an EF0 tornado on October 7, 2010 near Harris Siding. The weather service has also logged 24 hail reports and 4 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.