Photo: Ellin Beltz · Public domainFEMA expects more hazard damage per building in Rio Dell than almost anywhere in the U.S., mostly from river and rain flooding
On FEMA’s National Risk Index, Rio Dell gets a D− for hazard risk: among the highest expected damage per building of U.S. towns, #840 of 847 in California. Most of that expected damage is river and rain flooding (69%), then earthquakes (30%). Flood insurance has paid 4 claims here since 1982.
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 Rio Dell 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 Rio Dell’s grade
River and rain flooding is 69% of the building damage FEMA expects in Rio Dell, and Rio Dell’s rate of river and rain flooding damage is in the top 1% of U.S. census tracts. Earthquakes add 30%, at a rate in the top 1% of U.S. census tracts.
D− #840 of 847 in California; among the highest expected damage per building of U.S. towns (21,298).
All of Rio Dell’s residents live in one census tract; the figures are that tract’s.
The typical California town has higher expected damage than 92% of U.S. towns; within the state, Rio Dell has more expected damage per building than 99% of California towns.
In dollars, FEMA expects about $7.5M a year in losses across Rio Dell: $6.8M to buildings, the rest to people and crops.
Does Rio Dell flood? Rarely: 4 flood claims since 1982
Every paid claim on a federal flood insurance policy in Rio Dell, from FEMA’s records: 2.4 per 1,000 homes, fewer than 57% of the 13,809 U.S. towns with a flood insurance record.
Rio Dell isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Humboldt County.1 federal disaster brought FEMA money to Rio Dell
Disasters that paid out in Rio Dell itself (aid to households or repair grants to the City of Rio Dell), newest first, with that year’s flood claims.
- 2005Severe Storms, Flooding, Mudslides, and Landslides$321K to the City of Rio Dell for repairs1 flood claim paid that year
Humboldt County has had 23 natural disasters declared by the President since 1953, most often floods, then severe storms. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Old photos of Rio Dell after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Rio Dell archive →Rio Dell and its neighbors
Rio Dell has the lowest expected damage per building of the 1 graded towns here. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Rio Dell | D−among the highest damage | river and rain flooding | 4 |
| Scotia | — | 405 residents; we grade 1,000+ | |
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 Rio Dell 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 Rio Dell
Is Rio Dell at risk for natural disasters?
On FEMA’s National Risk Index, Rio Dell has among the highest expected damage per building of U.S. towns: D− for hazard risk, #840 of 847 in California. Most of the expected damage is river and rain flooding (69%) and earthquakes (30%). 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 Rio Dell flood?
Flood insurance has paid 4 claims in Rio Dell since 1982, $31K in all, or 2.4 per 1,000 homes, fewer than 57% of U.S. towns with a flood insurance record. 1 properties have flooded more than once.
Is Rio Dell 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 Humboldt County, 10% of homes in mapped flood zones carry federal flood insurance, and 0.7% of all homes do.
How much is flood insurance in Rio Dell?
FEMA’s Community Rating System list shows no discount for Rio Dell’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 Rio Dell?
By FEMA money that reached Rio Dell, Severe Storms, Flooding, Mudslides, and Landslides (2005): $321K to the City of Rio Dell for repairs.
Is Rio Dell at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (69%), and Rio Dell’s rate for it is in the top 1% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Rio Dell.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Rio Dell’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.