Photo: Perfect Zero from Los Angeles, CA, US · CC BY 2.0On FEMA’s figures, Mammoth Lakes faces more hazard damage per building than 83% of U.S. towns, mostly from earthquakes
On FEMA’s National Risk Index, Mammoth Lakes gets a C− for hazard risk: higher expected damage per building than 83% of U.S. towns, #200 of 847 in California. Most of that expected damage is earthquakes (52%), then river and rain flooding (45%). Flood insurance has paid 2 claims here since 2023.
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 Mammoth Lakes faces
Each hazard’s share of the building damage FEMA expects here, and how its rate compares with the rest of the country.
Earthquakes
River and rain flooding
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 Mammoth Lakes’ grade
Earthquakes are 52% of the building damage FEMA expects in Mammoth Lakes, and Mammoth Lakes’ rate of earthquakes damage is in the top 9% of U.S. census tracts. Wildfire adds 3%, at a rate in the top 8% of U.S. census tracts.
C− #200 of 847 in California; higher expected damage per building than 83% of U.S. towns (21,298).
Mammoth Lakes’ residents live in 2 census tracts; FEMA’s figures are combined by where they live.
The typical California town has higher expected damage than 92% of U.S. towns; within the state, Mammoth Lakes has less expected damage per building than 76% of California towns.
In dollars, FEMA expects about $9.3M a year in losses across Mammoth Lakes: $5.9M to buildings, the rest to people and crops.
Does Mammoth Lakes flood? Rarely: 2 flood claims since 2023
Every paid claim on a federal flood insurance policy in Mammoth Lakes, from FEMA’s records: 0.2 per 1,000 homes, fewer than 97% of the 13,809 U.S. towns with a flood insurance record.
Mammoth Lakes isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Mono County.4 federal disasters brought FEMA money to Mammoth Lakes
Disasters that paid out in Mammoth Lakes itself (aid to households or repair grants to the Town of Mammoth Lakes), newest first, with that year’s flood claims.
- 2023Severe Winter Storms, Straight-line Winds, Flooding, Landslides, and Mudslides455 households applied for aid$390K aid approved$732K to the Town of Mammoth Lakes for repairs1 flood claim paid that year
- 2017Severe Winter Storms, Flooding, and Mudslides$46K to the Town of Mammoth Lakes for repairs
- 2017Severe Winter Storms, Flooding, and Mudslides$7K to the Town of Mammoth Lakes for repairs
- 2017Severe Winter Storms, Flooding, and Mudslides$14K to the Town of Mammoth Lakes for repairs
Mono County has had 10 natural disasters declared by the President since 1953, most often floods, then severe storms. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Old photos of Mammoth Lakes after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Mammoth Lakes archive →Get ready for what Mammoth Lakes faces
A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.
- Drop, cover and hold on.
- Strap tall furniture and the water heater to the wall.
- Know how to shut off the gas.
- 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.
- 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 Mammoth Lakes
Is Mammoth Lakes at risk for natural disasters?
On FEMA’s National Risk Index, Mammoth Lakes has higher expected damage per building than 83% of U.S. towns: C− for hazard risk, #200 of 847 in California. Most of the expected damage is earthquakes (52%) and river and rain flooding (45%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Mammoth Lakes flood?
Flood insurance has paid 2 claims in Mammoth Lakes since 2023, $26K in all, or 0.2 per 1,000 homes, fewer than 97% of U.S. towns with a flood insurance record.
Is Mammoth Lakes 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 Mono County, 19% of homes in mapped flood zones carry federal flood insurance, and 1.1% of all homes do.
How much is flood insurance in Mammoth Lakes?
FEMA’s Community Rating System list shows no discount for Mammoth Lakes’ flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
What was the biggest storm in Mammoth Lakes?
By FEMA money that reached Mammoth Lakes, Severe Winter Storms, Straight-line Winds, Flooding, Landslides, and Mudslides (2023): 455 households applied for aid, $390K approved, and $732K to the Town of Mammoth Lakes for repairs.
Is Mammoth Lakes at risk from earthquakes?
It is the largest share of the building damage FEMA expects here (52%), and Mammoth Lakes’ rate for it is in the top 9% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Mammoth Lakes.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Mammoth Lakes’ 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.