Natural hazards · Alum Rock

Alum Rock, CA natural hazards

Most of the natural-hazard damage FEMA expects in Alum Rock comes from earthquakes, and overall the risk is very high for a U.S. community.

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

Expected damage

How exposed is Alum Rock?

Very high

vs. U.S. communities

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

Earthquakes81%Inland flooding17%Everything else3%

By hazard

What Alum Rock faces

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

Earthquakes

81% of expected damage

Well above average · among the top 1% of U.S. places

Inland flooding

17% of expected damage

Above average · higher than 63% of U.S. places

Recorded about 2 times a year in the area

Lower here

TornadoesHailHeat wavesLandslidesStrong windLightning

Not a risk here

Coastal floodingHurricanesIce stormsWinter weatherCold wavesWildfireDroughtAvalanchesTsunamisVolcanic 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 Alum Rock flood?

FEMA's records show no paid flood insurance claims in Alum Rock.

of homes in flood zones
are insured

of all homes
are insured

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

Insurance rates: Santa Clara County.

Disasters that hit Alum Rock

Federal disasters declared here

None of the disasters declared for Santa Clara County shows FEMA aid or repair money reaching Alum Rock itself in FEMA’s records.

Brought FEMA money into Alum RockDeclared for Santa Clara County only

Santa Clara County has had 22 natural disasters declared since 1953, most often floods and fires.

Around Alum Rock

Alum Rock and the towns around it

Very lowLowModerateHighVery high

San Josemostly earthquakesVery high

Alum Rockmostly earthquakesVery high

East Foothillsmostly 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. Alum Rock covers 3 census tracts, combined by population.

Money that reached townFlood claims are matched to Alum Rock’s own flood-insurance community; household aid to the registrant’s city; repair grants to Alum Rock. 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 Alum Rock total about $7.9M 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.