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Lewis and Clark County, Montana

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

Relatively Low overall risk
7th of 56highest risk in Montana
$35Mexpected losses a year
14federal declarations
1 in 167homes with flood insurance
Photo: Bold Frontiers, CC BY 2.0

Lewis and Clark County, Montana has a relatively low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is higher than 71% of US counties. It ranks 7th of 56 counties in Montana. The costliest hazards here are cold waves, inland flooding and earthquakes. FEMA estimates about $35 million a year in expected losses, or roughly $491 per resident. Since 1975 it has been included in 14 federal disaster or emergency declarations for natural events (6 major disasters). The most recent was in July 2024 (Horse Gulch Fire). Fewer than 1 in 100 homes here carry federal flood insurance (176 policies). Since 1978, federal flood insurance has paid about $432,000 on 102 claims here.

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

Top risks in Lewis and Clark County

$12.9 million a yearExpected losses. Damaging events about 6 times a year.
  • Insulate pipes in outside walls, crawl spaces and garages.
  • Know how to shut off the main water valve.
$12.4 million a yearExpected losses. Damaging events about once a year.
  • 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.
$3.8 million a yearExpected losses. Damaging events about once every 135 years.
  • Ask whether an older house is bolted to its foundation.
  • Consider separate earthquake insurance where risk is high.
HazardRatingScoreExpected loss a year
Cold waveHigh94.6
$13M
Inland floodingLow64.6
$12M
EarthquakeLow86.8
$4M
WildfireModerate92.8
$3M
Winter weatherVery High98.1
$2M
LightningModerate66.3
$504K
AvalancheModerate79.8
$457K
Strong windLow21.2
$226K
Heat waveVery Low35.4
$213K
LandslideModerate95.2
$154K
TornadoVery Low8.9
$62K
HailVery Low10.2
$38K
Ice stormVery Low15.7
$12K
DroughtVery Low22.8
$9K

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 high in FEMA's measures.

Federal disaster history

Recent disasters nationwide ›

Declarations by decade

Federal declarations for natural events that included Lewis and Clark County. 2020s bar runs to November 2026.

By type

Fire8
Flood3
Severe Storm2
Hurricane1

Most recent

Jul 12, 2024Horse Gulch FireFire management
Jul 28, 2019North Hills FireFire management
Oct 31, 2018FloodingMajor disaster
Sep 9, 2017Alice Creek FireFire management
Jun 26, 2012Corral FireFire management
Jun 17, 2011Severe Storms and FloodingMajor disaster
Sep 16, 2007Country Club FireFire management
Sep 13, 2005Hurricane Katrina EvacuationEmergency
Aug 20, 2003Mt-Lincoln Fire Complex - 08/14/2003Fire management
Aug 30, 2000WildfiresMajor disaster
Show all 14
Jul 24, 2000Mt - Central Zone 3B Fire ComplexFire management
Feb 23, 1996Severe Storms, Flooding, and Ice JamsMajor disaster
May 27, 1981Severe Storms & FloodingMajor disaster
Jun 28, 1975Rains, Showmelt, Storms & FloodingMajor disaster

Montana also had 36 statewide declarations that did not name single counties.

Storm history since 1953

Tornado risk by county ›

The National Weather Service has logged 318 storm reports in Lewis and Clark County since 1953, with 0 deaths and 14 injuries and about $5.9 million in reported damage. The strongest on record here was an F0 tornado on June 27, 1997 near Helena.

4tornadoes
118hail reports, largest 3 inches
117damaging thunderstorm winds
39floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
Jun 27, 1997F0Helena0 / 0
Jul 22, 1960F0–0 / 0
Jul 9, 1992F0–0 / 0
Jun 7, 1953n/a–0 / 0

Most damaging storms

DateTypeNearDamage
Jul 23, 2000WildfireHelena$3M
Aug 1, 2000WildfireHelena$3M
Jul 3, 2022Flash FloodHelena$700K
Apr 9, 2023FloodBirdseye$100K
Jul 20, 2012Flash FloodFt Harrison$50K
Jul 31, 2025Debris FlowCanyon Ferry$11K

Source: NOAA Storm Events Database, county-based reports through Jul 23, 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 and Clark County

Check your address flood zone ›
0.6%of homes have federal flood insurance (176 policies)
13.7%of homes in mapped high-risk flood zones are insured
$431,717paid on 102 flood claims since 1978
2018costliest year, with $175,800 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 Lewis and Clark County

$393,500median home value (Montana $375,800, US $332,700)
1982median year homes were built (Montana 1981, US 1980)
48%of homes built before 1980, before many modern wind, quake and flood building rules
9.6%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; 34,082 housing units.

Compare in Montana

All 56 ›
Largest countiesOverall riskTop hazard
Yellowstone CountyModerateInland flooding
Gallatin CountyModerateEarthquake
Missoula CountyLowInland flooding
Flathead CountyModerateInland flooding
Cascade CountyModerateInland flooding
Lewis and Clark CountyLowCold wave
Ravalli CountyLowWildfire
Silver Bow CountyVery LowCold wave

Neighboring counties

CountyOverall riskDeclarations
Flathead CountyModerate13
Cascade CountyModerate5
Jefferson CountyVery Low9
Powell CountyVery Low15
Broadwater CountyVery Low10
Teton CountyVery Low10
Meagher CountyVery Low8

Cities in Lewis and Clark County

Common questions about Lewis and Clark County

What is the biggest natural hazard in Lewis and Clark County?

Cold wave has the highest expected yearly losses in Lewis and Clark County, about $12.9 million a year in FEMA's estimate. Inland flooding is second at $12.4 million.

How many federal disasters has Lewis and Clark County had?

Lewis and Clark County has been included in 14 federal disaster or emergency declarations for natural events since 1975, including 6 major disasters. The most recent was Horse Gulch Fire in July 2024.

Is Lewis and Clark County a high-risk place to live?

Its overall rating is Relatively Low, 7th highest of 56 in Montana. 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 and Clark County?

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

NOAA records list 4 tornadoes in Lewis and Clark County since 1950. The strongest was an F0 tornado on June 27, 1997 near Helena. The weather service has also logged 118 hail reports and 39 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.