Natural hazards · Alta Sierra

Alta Sierra, CA natural hazards

Most of the natural-hazard damage FEMA expects in Alta Sierra comes from inland flooding, and overall the risk is high for a U.S. community.

FEMA National Risk Index, December 2025 · OpenFEMA claims, aid & declarations

Expected damage

How exposed is Alta Sierra?

High

vs. U.S. communities

FEMA expects yearly storm and flood damage to homes and buildings in Alta Sierra to be higher than in 67% of U.S. communities, mostly from inland flooding and wildfires.

Inland flooding67%Wildfire25%Everything else9%

By hazard

What Alta Sierra faces

Each hazard’s share of the damage FEMA expects here, and how that compares with the rest of the country.

Inland flooding

67% of expected damage

Well above average · higher than 76% of U.S. places

Recorded about once a year in the area

Wildfire

25% of expected damage

Well above average · higher than 98% of U.S. places

Lower here

TornadoesHailWinter weatherHeat wavesEarthquakesLandslidesStrong windLightningVolcanic activity

Not a risk here

Coastal floodingHurricanesIce stormsCold wavesDroughtAvalanchesTsunamis

Flood risk changes street by street. Check a specific address on FEMA’s flood map, and ask about flood insurance before you buy.

Flood insurance claims

Does Alta Sierra flood?

FEMA's records show no paid flood insurance claims in Alta Sierra.

of homes in flood zones
are insured

of all homes
are insured

No community discount. Alta Sierra isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.

Insurance rates: Nevada County.

Disasters that hit Alta Sierra

Federal disasters declared here

None of the disasters declared for Nevada County shows FEMA aid or repair money reaching Alta Sierra itself in FEMA’s records.

Brought FEMA money into Alta SierraDeclared for Nevada County only

Nevada County has had 20 natural disasters declared since 1953, most often fires and severe storms.

About these numbers

How to read this page

An average, not a forecastFEMA’s National Risk Index estimates the damage 18 kinds of natural hazards cause in a typical year, from decades of records and models. A quiet decade can follow a bad year.

Compared by rate“Higher than N%” compares yearly damage as a share of what’s here, so a big city isn’t rated riskier just for having more buildings. Alta Sierra covers 1 census tract, combined by population.

Money that reached townFlood claims are matched to Alta Sierra’s own flood-insurance community; household aid to the registrant’s city; repair grants to Alta Sierra. FEMA’s model follows property values, so a place that recently lost many homes can rate lower than it feels.

FEMA’s expected losses across Alta Sierra total about $2.2M a year, counting buildings, people and crops.

Sources: FEMA National Risk Index (December 2025); 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. Census tracts: U.S. Census Bureau.