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Granite County, Montana

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

Very Low overall risk
40th of 56highest risk in Montana
$4Mexpected losses a year
6federal declarations
1 in 200homes with flood insurance
Photo: U.S. Geological Survey, public domain

Granite County, Montana has a very low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is lower than 91% of US counties. It ranks 40th of 56 counties in Montana. The costliest hazards here are inland flooding, avalanches and wildfires. FEMA estimates about $4.2 million a year in expected losses, or roughly $1,272 per resident. Since 1981 it has been included in 6 federal disaster or emergency declarations for natural events (4 major disasters). The most recent was in June 2011 (severe storms and flooding). Only 15 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 Granite County

$1.3 million a yearExpected losses. Damaging events about once every 4 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.
$1 million a yearExpected losses. Damaging events about once every 5 years.
  • Check avalanche forecasts before backcountry trips.
  • Ask about slide paths near mountain homes.
$1 million a yearExpected losses. Damaging events about once every 180 years.
  • Clear dry plants and debris within 5 feet of the house.
  • Get home insurance quotes early; availability varies by area.
HazardRatingScoreExpected loss a year
Inland floodingVery Low11.1
$1M
AvalancheHigh86.3
$1M
WildfireLow88.6
$1M
Cold waveLow34.4
$470K
EarthquakeVery Low37.7
$120K
LandslideModerate91.9
$68K
Winter weatherLow48.8
$56K
Ice stormLow29.1
$27K
LightningVery Low8.2
$24K
HailVery Low6.5
$17K
Strong windVery Low3.2
$15K
TornadoVery Low2.7
$5K
Heat waveVery Low4.2
$4K
DroughtVery Low17.0
$2K

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 relatively low in FEMA's measures.

Federal disaster history

Recent disasters nationwide ›

Declarations by decade

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

By type

Flood2
Fire2
Hurricane1
Severe Storm1

Most recent

Jun 17, 2011Severe Storms and FloodingMajor disaster
Sep 13, 2005Hurricane Katrina EvacuationEmergency
Aug 30, 2000WildfiresMajor disaster
Aug 5, 2000Mt-Southwestern Zone Two Fire ComplexFire management
Mar 15, 1986Heavy Rains, Landslides & FloodingMajor disaster
May 27, 1981Severe Storms & FloodingMajor disaster

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

Storm history since 1958

Tornado risk by county ›

The National Weather Service has logged 58 storm reports in Granite County since 1958 and about $90,500 in reported damage. The strongest on record here was an F0 tornado on May 4, 1971.

2tornadoes
31hail reports, largest 2 inches
15damaging thunderstorm winds
6floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
May 4, 1971F0–0 / 0
Aug 11, 1988F0–0 / 0

Most damaging storms

DateTypeNearDamage
Jun 13, 2017FloodNimrod$51K
Aug 9, 2013Flash FloodNew Chicago$25K
Jul 4, 2008HailPhilipsburg$12K
Aug 9, 2008Heavy RainBearmouth$1K
Aug 5, 2010Flash FloodDrummond$1K
Aug 9, 2013Flash FloodDrummond$500

Source: NOAA Storm Events Database, county-based reports through Jul 17, 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 Granite County

Check your address flood zone ›
0.5%of homes have federal flood insurance (15 policies)
5.6%of homes in mapped high-risk flood zones are insured
$16,934paid on 7 flood claims since 1978
2011costliest year, with $12,415 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 Granite County

$352,700median home value (Montana $375,800, US $332,700)
1980median year homes were built (Montana 1981, US 1980)
51%of homes built before 1980, before many modern wind, quake and flood building rules
10.3%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; 2,602 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
Missoula CountyLow19
Ravalli CountyLow11
Deer Lodge CountyVery Low8
Powell CountyVery Low15

Common questions about Granite County

What is the biggest natural hazard in Granite County?

Inland flooding has the highest expected yearly losses in Granite County, about $1.3 million a year in FEMA's estimate. Avalanche is second at $1 million.

How many federal disasters has Granite County had?

Granite County has been included in 6 federal disaster or emergency declarations for natural events since 1981, including 4 major disasters. The most recent was Severe Storms and Flooding in June 2011.

Is Granite County a high-risk place to live?

Its overall rating is Very Low, 40th 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 Granite County?

Standard home insurance does not cover flooding. About 1 in 200 homes in Granite 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 Granite County had?

NOAA records list 2 tornadoes in Granite County since 1950. The strongest was an F0 tornado on May 4, 1971. The weather service has also logged 31 hail reports and 6 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.