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Lemhi County, Idaho

Natural disaster risk, federal disaster history and flood insurance facts.

Very Low overall risk
20th of 44highest risk in Idaho
$11Mexpected losses a year
3federal declarations
1 in 167homes with flood insurance
Photo: U.S. Geological Survey, public domain

Lemhi County, Idaho has a very low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is lower than 59% of US counties. It ranks 20th of 44 counties in Idaho. The costliest hazards here are inland flooding, wildfires and lightning. FEMA estimates about $11 million a year in expected losses, or roughly $1,433 per resident. Since 1984 it has been included in 3 federal disaster or emergency declarations for natural events (2 major disasters). The most recent was in September 2005 (Hurricane Katrina). Only 31 homes here carry federal flood insurance. Since 1978, federal flood insurance has paid about $267,000 on 24 claims here.

FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.

Top risks in Lemhi County

$7.9 million a yearExpected losses. Damaging events about once every 2 years.
  • 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.

Wildfire

Moderate
$2 million a yearExpected losses. Damaging events about once every 240 years.
  • Clear dry plants and debris within 5 feet of the house.
  • Get home insurance quotes early; availability varies by area.

Lightning

Moderate
$590,532 a yearExpected losses. Damaging events about 31 times a year.
  • Go indoors when you hear thunder.
  • Use surge protectors for electronics.
HazardRatingScoreExpected loss a year
Inland floodingLow59.8
$8M
WildfireModerate93.2
$2M
LightningModerate78.3
$591K
Cold waveLow30.7
$383K
EarthquakeVery Low53.5
$288K
LandslideModerate95.7
$139K
Strong windVery Low4.3
$25K
Heat waveVery Low12.5
$23K
Winter weatherVery Low21.9
$17K
HailVery Low4.8
$10K
TornadoVery Low3.1
$7K
Ice stormVery Low6.9
$3K
AvalancheVery Low60.1
$1K
DroughtVery Low14.4
$355
Volcanic activityVery Low13.0
$0

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 moderate 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 Lemhi County. 2020s bar runs to November 2026.

By type

Snowstorm1
Fire1
Hurricane1

Most recent

Sep 13, 2005Hurricane KatrinaEmergency
Sep 1, 2000WildfiresMajor disaster
Feb 16, 1984Ice Jams and FloodingMajor disaster

Idaho also had 16 statewide declarations that did not name single counties.

Storm history since 1956

Tornado risk by county ›

The National Weather Service has logged 134 storm reports in Lemhi County since 1956, with 3 deaths and 3 injuries and about $1.4 million in reported damage. The strongest on record here was an F1 tornado on June 15, 1987.

3tornadoes
32hail reports, largest 1.75 inches
57damaging thunderstorm winds
24floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
Jun 15, 1987F1–0 / 0
Aug 24, 1984F1–0 / 0
Jun 1, 1956F1–0 / 0

Most damaging storms

DateTypeNearDamage
Aug 1, 2013HailSalmon$490K
Jun 15, 1987Tornado–$250K
Jun 30, 2024Flash FloodShoup$250K
Jun 19, 2025Thunderstorm WindLeadore$70K
Jun 21, 2009FloodLemhi$50K
Jan 29, 2023FloodBaker$50K

Source: NOAA Storm Events Database, county-based reports through Jan 27, 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 Lemhi County

Check your address flood zone ›
0.6%of homes have federal flood insurance (31 policies)
0%of homes in mapped high-risk flood zones are insured
$267,102paid on 24 flood claims since 1978
2017costliest year, with $81,090 paid

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 Lemhi County

$326,100median home value (Idaho $418,600, US $332,700)
1979median year homes were built (Idaho 1991, US 1980)
53%of homes built before 1980, before many modern wind, quake and flood building rules
15.6%of homes are mobile homes, which are the least safe in tornadoes and high winds

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; 4,676 housing units.

Compare in Idaho

All 44 ›
Largest countiesOverall riskTop hazard
Ada CountyModerateInland flooding
Canyon CountyLowInland flooding
Kootenai CountyLowInland flooding
Bonneville CountyModerateInland flooding
Twin Falls CountyLowInland flooding
Bannock CountyLowWildfire
Madison CountyLowInland flooding
Bingham CountyLowInland flooding

Neighboring counties

CountyOverall riskDeclarations
Ravalli County, MTLow11
Idaho CountyLow16
Valley CountyLow10
Beaverhead County, MTLow4
Custer CountyLow5
Butte CountyVery Low4
Clark CountyVery Low2

Common questions about Lemhi County

What is the biggest natural hazard in Lemhi County?

Inland flooding has the highest expected yearly losses in Lemhi County, about $7.9 million a year in FEMA's estimate. Wildfire is second at $2 million.

How many federal disasters has Lemhi County had?

Lemhi County has been included in 3 federal disaster or emergency declarations for natural events since 1984, including 2 major disasters. The most recent was Hurricane Katrina in September 2005.

Is Lemhi County a high-risk place to live?

Its overall rating is Very Low, 20th 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 Lemhi County?

Standard home insurance does not cover flooding. About 1 in 167 homes in Lemhi 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 Lemhi County had?

NOAA records list 3 tornadoes in Lemhi County since 1950. The strongest was an F1 tornado on June 15, 1987. The weather service has also logged 32 hail reports and 24 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.