Natural hazards · Atherton

Atherton, CA natural hazards

Most of the natural-hazard damage FEMA expects in Atherton comes from earthquakes, and overall the risk is very high for a U.S. community. Flood insurance has paid 8 claims here since 1982. 2 federal disasters brought FEMA money into town.

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

Expected damage

How exposed is Atherton?

Very high

vs. U.S. communities

FEMA expects yearly storm and flood damage to homes and buildings in Atherton to be higher than in 91% of U.S. communities, mostly from earthquakes and inland flooding.

Earthquakes58%Inland flooding42%

By hazard

What Atherton faces

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

Earthquakes

58% of expected damage

Well above average · higher than 96% of U.S. places

Inland flooding

42% of expected damage

Well above average · higher than 89% of U.S. places

Recorded about once a year in the area

Lower here

TornadoesHailHeat wavesWildfireLandslidesStrong windLightningDrought

Not a risk here

Coastal floodingHurricanesIce stormsWinter weatherCold wavesAvalanchesTsunamisVolcanic activity

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 Atherton flood?

Every paid claim on a federal flood insurance policy in Atherton, from FEMA’s records.

8paid claims since 1982

$388Kpaid to owners

0homes flooded more than once

19822026

Biggest named events

Pineapple Express - Southern: 5 claims, $235K
Winter storm: 1 claim, $5K
California Atmospheric River: 1 claim, $143K

of homes in flood zones
are insured

of all homes
are insured

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

Insurance rates: San Mateo County.

Disasters that hit Atherton

2 federal disasters brought FEMA money here

Disasters the President declared that paid out in Atherton itself: aid to households, or repair grants to the Town of Atherton.

Brought FEMA money into AthertonDeclared for San Mateo County only

2022

Severe Winter Storms, Flooding, Landslides, and Mudslides

11 households applied for aid $15K aid approved $86K to the Town of Atherton for repairs

2020

Wildfires

29 households applied for aid $8K aid approved

San Mateo County has had 21 natural disasters declared since 1953, most often floods and severe storms.

Around Atherton

Atherton and the towns around it

Very lowLowModerateHighVery high

Athertonmostly earthquakesVery high

North Fair Oaksmostly earthquakesVery high

Redwood Citymostly earthquakesVery high

Woodsidemostly earthquakesVery high

Menlo Parkmostly earthquakesVery high

West Menlo Parkmostly earthquakesVery high

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. Atherton covers 2 census tracts, combined by population.

Money that reached townFlood claims are matched to Atherton’s own flood-insurance community; household aid to the registrant’s city; repair grants to the Town of Atherton. 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 Atherton total about $15.0M 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.