On FEMA’s figures, Alum Rock faces more hazard damage per building than 95% of U.S. towns, mostly from earthquakes
On FEMA’s National Risk Index, Alum Rock gets a D for hazard risk: higher expected damage per building than 95% of U.S. towns, #533 of 847 in California. Most of that expected damage is earthquakes (73%), then river and rain flooding (27%). 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 Alum Rock 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 Alum Rock’s grade
Earthquakes are 73% of the building damage FEMA expects in Alum Rock, and Alum Rock’s rate of earthquakes damage is in the top 1% of U.S. census tracts. Next is river and rain flooding at 27% (higher than 63% of U.S. census tracts).
D #533 of 847 in California; higher expected damage per building than 95% of U.S. towns (21,298).
Alum Rock’s residents live in 4 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, Alum Rock has more expected damage per building than 63% of California towns.
In dollars, FEMA expects about $6.0M a year in losses across Alum Rock: $3.7M to buildings, the rest to people and crops.
Does Alum Rock flood? No paid flood claims on record
FEMA’s records show no paid flood insurance claims in Alum Rock. That’s not a promise: most homes don’t carry flood insurance, so small floods go unrecorded.
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.The storms Alum Rock remembers
None of the 19 disasters declared for Santa Clara County shows FEMA aid or repair money reaching Alum Rock itself in FEMA’s records, so these are its biggest flood-claim years.
Santa Clara County has had 19 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 3 FEMA wildfire suppression grants (Fire Management Assistance, not a disaster declaration) for fires in Santa Clara County, 2002–2020.
Alum Rock and its neighbors
Alum Rock is 2nd of the 3 graded towns here, from least expected damage per building to most. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| East Foothills | Dmore damage than 95% | earthquakes | 2 |
| Alum Rock | Dmore damage than 95% | earthquakes | 0 |
| San Jose | D−more damage than 97% | earthquakes | 389 |
Hazard risk = FEMA’s expected yearly building damage per dollar of building value, vs. the 21,298 U.S. towns we grade; the map is shaded by fifths of the same scale. Flood claims = paid federal flood insurance claims on record.
Get ready for what Alum Rock 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 Alum Rock
Is Alum Rock at risk for natural disasters?
On FEMA’s National Risk Index, Alum Rock has higher expected damage per building than 95% of U.S. towns: D for hazard risk, #533 of 847 in California. Most of the expected damage is earthquakes (73%) and river and rain flooding (27%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Is Alum Rock 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 Santa Clara County, 22% of homes in mapped flood zones carry federal flood insurance, and 1.7% of all homes do.
How much is flood insurance in Alum Rock?
FEMA’s Community Rating System list shows no discount for Alum Rock’s flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
Is Alum Rock at risk from earthquakes?
It is the largest share of the building damage FEMA expects here (73%), and Alum Rock’s rate for it is in the top 1% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Alum Rock.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Alum Rock’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.