Kahaluu Taro Lo'i · Photo: Joel Bradshaw · Public domainFEMA puts Ahuimanu’s expected hazard damage per building above that of 88% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Ahuimanu gets a D for hazard risk: higher expected damage per building than 88% of U.S. towns, #19 of 93 in Hawaii. Most of that expected damage is river and rain flooding (75%), then tsunamis (11%). Flood insurance has paid 12 claims here since 1978.
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 Ahuimanu 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
Tsunamis
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 Ahuimanu’s grade
River and rain flooding is 75% of the building damage FEMA expects in Ahuimanu, and Ahuimanu’s rate of river and rain flooding damage is in the top 10% of U.S. census tracts. Tsunamis add 11%, at a rate in the top 1% of U.S. census tracts.
D #19 of 93 in Hawaii; higher expected damage per building than 88% of U.S. towns (21,298).
Ahuimanu’s residents live in 4 census tracts; FEMA’s figures are combined by where they live.
The typical Hawaii town has higher expected damage than 96% of U.S. towns; within the state, Ahuimanu has less expected damage per building than 80% of Hawaii towns.
In dollars, FEMA expects about $3.5M a year in losses across Ahuimanu: $3.1M to buildings, the rest to people and crops.
Does Ahuimanu flood? Sometimes: 12 flood claims since 1978
Every paid claim on a federal flood insurance policy in Ahuimanu, from FEMA’s records: 3.9 per 1,000 homes, more than 54% of the 13,809 U.S. towns with a flood insurance record.
Ahuimanu isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Honolulu County.The storms Ahuimanu remembers
None of the 18 disasters declared for Honolulu County shows FEMA aid or repair money reaching Ahuimanu itself in FEMA’s records, so these are its biggest flood-claim years.
- 20184 flood claims paidThe year of Tropical Storm Olivia, declared for Honolulu County
- 19822 flood claims paidThe year of Typhoon Iwa, declared for Honolulu County
- 19942 flood claims paidNo declaration for the county that year
Honolulu County has had 18 natural disasters declared by the President since 1953, most often severe storms, then floods.
Also 4 FEMA wildfire suppression grants (Fire Management Assistance, not a disaster declaration) for fires in Honolulu County, 2005–2025.
Old photos of Ahuimanu after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Ahuimanu archive →Ahuimanu and its neighbors
Ahuimanu is 2nd of the 3 graded towns here, from least expected damage per building to most. Tap a town to see its hazards.
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 Ahuimanu 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.
- Strong shaking or a sudden drop in the sea means head for high ground now.
- Learn the tsunami route signs near the shore.
- Stay away until officials say it’s safe.
- 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 Ahuimanu
Is Ahuimanu at risk for natural disasters?
On FEMA’s National Risk Index, Ahuimanu has higher expected damage per building than 88% of U.S. towns: D for hazard risk, #19 of 93 in Hawaii. Most of the expected damage is river and rain flooding (75%) and tsunamis (11%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Ahuimanu flood?
Flood insurance has paid 12 claims in Ahuimanu since 1978, $365K in all, or 3.9 per 1,000 homes, more than 54% of U.S. towns with a flood insurance record.
Is Ahuimanu 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 Honolulu County, 54% of homes in mapped flood zones carry federal flood insurance, and 4.1% of all homes do.
How much is flood insurance in Ahuimanu?
FEMA’s Community Rating System list shows no discount for Ahuimanu’s flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
Is Ahuimanu at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (75%), and Ahuimanu’s rate for it is in the top 10% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Ahuimanu.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Ahuimanu’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.