More hazard damage per building is expected in Byron than in 94% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Byron gets a D for hazard risk: higher expected damage per building than 94% of U.S. towns. Most of that expected damage is river and rain flooding (53%), then earthquakes (37%). Flood insurance has paid 4 claims here since 1995.
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 Byron 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
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 Byron’s grade
River and rain flooding is 53% of the building damage FEMA expects in Byron, and Byron’s rate of river and rain flooding damage is in the top 10% of U.S. census tracts. Earthquakes add 37%, at a rate in the top 8% of U.S. census tracts.
D higher expected damage per building than 94% of U.S. towns (21,298).
All of Byron’s residents live in one census tract; the figures are that tract’s.
In dollars, FEMA expects about $2.4M a year in losses across Byron: $1.5M to buildings, the rest to people and crops.
Does Byron flood? Rarely: 4 flood claims since 1995
Every paid claim on a federal flood insurance policy in Byron, from FEMA’s records: 7.5 per 1,000 homes, more than 68% of the 13,809 U.S. towns with a flood insurance record.
- The California Atmospheric River3 claims · $151K
Byron 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.1 federal disaster brought FEMA money to Byron
Disasters that paid out in Byron itself (aid to households or repair grants to Byron), newest first, with that year’s flood claims.
- 2022Severe Winter Storms, Flooding, Landslides, and Mudslides10 households applied for aid$7K 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 Byron after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Byron archive →Get ready for what Byron 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.
- 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 Byron
Is Byron at risk for natural disasters?
On FEMA’s National Risk Index, Byron has higher expected damage per building than 94% of U.S. towns: D for hazard risk. Most of the expected damage is river and rain flooding (53%) and earthquakes (37%). The figures are for the one census tract the town shares with its neighbors. This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Byron flood?
Flood insurance has paid 4 claims in Byron since 1995, $152K in all, or 7.5 per 1,000 homes, more than 68% of U.S. towns with a flood insurance record. The most claims came from California Atmospheric River (3).
Is Byron 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 Byron?
FEMA’s Community Rating System list shows no discount for Byron’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 Byron?
By FEMA money that reached Byron, Severe Winter Storms, Flooding, Landslides, and Mudslides (2022): 10 households applied for aid, $7K approved. By flood claims, California Atmospheric River: 3 paid, $151K.
Is Byron at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (53%), and Byron’s rate for it is in the top 10% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Byron.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Byron’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.