Photo: FASTILY · CC BY-SA 4.0More hazard damage per building is expected in Blackhawk than in 95% of U.S. towns, led by river and rain flooding
On FEMA’s National Risk Index, Blackhawk gets a D− for hazard risk: higher expected damage per building than 95% of U.S. towns, #586 of 847 in California. Most of that expected damage is river and rain flooding (41%), then earthquakes (38%). Flood insurance has paid 1 claim here since 1991.
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 Blackhawk 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
Wildfire
Landslides
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 Blackhawk’s grade
River and rain flooding is 41% of the building damage FEMA expects in Blackhawk, and Blackhawk’s rate of river and rain flooding damage is higher than 86% of U.S. census tracts. Earthquakes add 38%, at a rate in the top 6% of U.S. census tracts.
D− #586 of 847 in California; higher expected damage per building than 95% of U.S. towns (21,298).
Blackhawk’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, Blackhawk has more expected damage per building than 69% of California towns.
In dollars, FEMA expects about $7.2M a year in losses across Blackhawk: $6.2M to buildings, the rest to people and crops.
Does Blackhawk flood? Rarely: 1 flood claim since 1991
Every paid claim on a federal flood insurance policy in Blackhawk, from FEMA’s records: 0.3 per 1,000 homes, fewer than 96% of the 13,809 U.S. towns with a flood insurance record.
Blackhawk 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.The storms Blackhawk remembers
None of the 17 disasters declared for Contra Costa County shows FEMA aid or repair money reaching Blackhawk itself in FEMA’s records, so these are its biggest flood-claim years.
- 19911 flood claims paidNo declaration for the county that year
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 Blackhawk after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Blackhawk archive →Blackhawk and its neighbors
Blackhawk is 3rd of the 4 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 |
|---|---|---|---|
| Camino Tassajara | Dmore damage than 93% | river and rain flooding | — |
| Diablo | Dmore damage than 94% | river and rain flooding | 1 |
| Blackhawk | D−more damage than 95% | river and rain flooding | 1 |
| Danville | D−more damage than 96% | river and rain flooding | 3 |
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 Blackhawk 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.
- Clear dead leaves and brush within 5 feet of the house.
- Sign up for local alerts and know two ways out.
- Keep N95 masks for smoky days.
- Watch for new cracks, tilting trees or suddenly muddy streams after heavy rain.
- Stay off steep slopes in a downpour.
- Leave if you hear rumbling upslope.
- 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 Blackhawk
Is Blackhawk at risk for natural disasters?
On FEMA’s National Risk Index, Blackhawk has higher expected damage per building than 95% of U.S. towns: D− for hazard risk, #586 of 847 in California. Most of the expected damage is river and rain flooding (41%) and earthquakes (38%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Blackhawk flood?
Flood insurance has paid 1 claim in Blackhawk since 1991, $775 in all, or 0.3 per 1,000 homes, fewer than 96% of U.S. towns with a flood insurance record.
Is Blackhawk 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 Blackhawk?
FEMA’s Community Rating System list shows no discount for Blackhawk’s flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
Is Blackhawk at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (41%), and Blackhawk’s rate for it is higher than 86% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Blackhawk.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Blackhawk’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.