Photo: Greg Gjerdingen · CC BY 2.0On FEMA’s figures, Big Sky faces more hazard damage per building than 80% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Big Sky gets a C− for hazard risk: higher expected damage per building than 80% of U.S. towns. Most of that expected damage is river and rain flooding (52%), then wildfire (32%). FEMA’s files show no paid flood insurance claims here.
Graded on FEMA’s expected yearly building damage per dollar of building value (NRI v1.20, December 2025), weighted by where residents live; flood claims are shown, not graded. How hazard risk is graded
What Big Sky faces
Each hazard’s share of the building damage FEMA expects here, and how its rate compares with the rest of the country.
River and rain flooding
Wildfire
Earthquakes
Shares are of FEMA’s expected building damage, the measure the grade uses; ranks compare each hazard’s building-damage rate with all 85,154 U.S. census tracts. In FEMA’s terms, river and rain flooding is FEMA’s “Inland Flooding” (rivers and streams overflowing their banks, or rain overwhelming drainage). FEMA defines coastal flooding as high or rising tides and storm surge, so surge damage is counted there. Drought isn’t listed: FEMA counts its losses in crops only.
What’s behind Big Sky’s grade
River and rain flooding is 52% of the building damage FEMA expects in Big Sky, and Big Sky’s rate of river and rain flooding damage is higher than 66% of U.S. census tracts. Wildfire adds 32%, at a rate in the top 2% of U.S. census tracts.
C− higher expected damage per building than 80% of U.S. towns (21,298).
Big Sky’s residents live in 3 census tracts; FEMA’s figures are combined by where they live.
In dollars, FEMA expects about $11.7M a year in losses across Big Sky: $2.8M to buildings, the rest to people and crops.
Does Big Sky flood? No paid flood claims on record
FEMA’s records show no paid flood insurance claims in Big Sky. That’s not a promise: most homes don’t carry flood insurance, so small floods go unrecorded.
Big Sky isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Gallatin County.The storms Big Sky remembers
None of the 4 disasters declared for Gallatin County shows FEMA aid or repair money reaching Big Sky itself in FEMA’s records, so these are its biggest flood-claim years.
Gallatin County has had 4 natural disasters declared by the President since 1953, most often severe storms, then floods. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Also 2 FEMA wildfire suppression grants (Fire Management Assistance, not a disaster declaration) for fires in Gallatin County, 2000–2020.
Get ready for what Big Sky faces
A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.
- Turn around at flooded roads: a foot of moving water can carry off a car.
- Flood insurance usually takes 30 days to start, so buy it before the forecast.
- Keep papers and medicines up high, in a grab-and-go bag.
- Clear dead leaves and brush within 5 feet of the house.
- Sign up for local alerts and know two ways out.
- Keep N95 masks for smoky days.
- Drop, cover and hold on.
- Strap tall furniture and the water heater to the wall.
- Know how to shut off the gas.
- Look up the address on FEMA’s flood map.
- Ask the seller or landlord whether it has ever flooded, and what flood insurance costs there.
- Get a flood insurance quote early: policies usually start 30 days after you buy.
Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.
Questions about natural hazards in Big Sky
Is Big Sky at risk for natural disasters?
On FEMA’s National Risk Index, Big Sky has higher expected damage per building than 80% of U.S. towns: C− for hazard risk. Most of the expected damage is river and rain flooding (52%) and wildfire (32%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Is Big Sky in a flood zone?
Flood zones are drawn street by street, so the answer depends on the address: look it up on FEMA’s flood map. In Gallatin County, 20% of homes in mapped flood zones carry federal flood insurance, and 0.8% of all homes do.
How much is flood insurance in Big Sky?
FEMA’s Community Rating System list shows no discount for Big Sky’s flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
Is Big Sky at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (52%), and Big Sky’s rate for it is higher than 66% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Big Sky.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Big Sky’s residents lived in the 2020 census; OpenFEMA: NFIP redacted claims, multiple-loss properties, community status book and residential penetration rates, housing assistance (owners and renters), public assistance funded projects, hazard mitigation properties and disaster declarations. Homes: Census ACS 2020–24. Preparedness tips: Ready.gov. FEMA’s model is an average of expected damage, not a forecast. How hazard risk is graded.