Photo: Richard Niewiroski Jr. · CC BY-SA 4.0More hazard damage per building is expected in Alamo than in 96% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Alamo gets a D− for hazard risk: higher expected damage per building than 96% of U.S. towns, #626 of 847 in California. Most of that expected damage is river and rain flooding (59%), then earthquakes (38%). 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 Alamo faces
Each hazard’s share of the building damage FEMA expects here, and how its rate compares with the rest of the country.
River and rain flooding
Earthquakes
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 Alamo’s grade
River and rain flooding is 59% of the building damage FEMA expects in Alamo, and Alamo’s rate of river and rain flooding damage is in the top 5% of U.S. census tracts. Earthquakes add 38%, at a rate in the top 6% of U.S. census tracts.
D− #626 of 847 in California; higher expected damage per building than 96% of U.S. towns (21,298).
Alamo’s residents live in 6 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, Alamo has more expected damage per building than 74% of California towns.
In dollars, FEMA expects about $22.4M a year in losses across Alamo: $20.6M to buildings, the rest to people and crops.
Does Alamo flood? No paid flood claims on record
FEMA’s records show no paid flood insurance claims in Alamo. That’s not a promise: most homes don’t carry flood insurance, so small floods go unrecorded.
Alamo isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Contra Costa County.2 federal disasters brought FEMA money to Alamo
Disasters that paid out in Alamo itself (aid to households or repair grants to Alamo), newest first, with that year’s flood claims.
- 2022Severe Winter Storms, Flooding, Landslides, and Mudslides35 households applied for aid$79K aid approved
- 2005Severe Storms, Flooding, Mudslides, and Landslides3 households applied for aid$2K aid approved
Contra Costa County has had 17 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.
Old photos of Alamo after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Alamo archive →Alamo and its neighbors
Alamo is 4th of the 5 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 |
|---|---|---|---|
| Diablo | Dmore damage than 94% | river and rain flooding | 1 |
| Danville | D−more damage than 96% | river and rain flooding | 3 |
| Walnut Creek | D−more damage than 96% | river and rain flooding | 67 |
| Alamo | D−more damage than 96% | river and rain flooding | 0 |
| Castle Hill | D−among the highest damage | river and rain flooding | 53 |
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 Alamo faces
A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.
- 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.
- Drop, cover and hold on.
- Strap tall furniture and the water heater to the wall.
- Know how to shut off the gas.
- 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 Alamo
Is Alamo at risk for natural disasters?
On FEMA’s National Risk Index, Alamo has higher expected damage per building than 96% of U.S. towns: D− for hazard risk, #626 of 847 in California. Most of the expected damage is river and rain flooding (59%) and earthquakes (38%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Is Alamo 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 Contra Costa County, 28% of homes in mapped flood zones carry federal flood insurance, and 0.9% of all homes do.
How much is flood insurance in Alamo?
FEMA’s Community Rating System list shows no discount for Alamo’s 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 Alamo?
By FEMA money that reached Alamo, Severe Winter Storms, Flooding, Landslides, and Mudslides (2022): 35 households applied for aid, $79K approved.
Is Alamo at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (59%), and Alamo’s rate for it is in the top 5% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Alamo.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Alamo’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.