Photo: The original uploader was Tijuana Brass at English Wikipedia. · CC BY-SA 3.0More hazard damage per building is expected in Waimanalo than in 84% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Waimanalo gets a C− for hazard risk: higher expected damage per building than 84% of U.S. towns, #8 of 93 in Hawaii. Most of that expected damage is river and rain flooding (79%), then earthquakes (11%). Flood insurance has paid 21 claims here since 1980.
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 Waimanalo 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
Tsunamis
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 Waimanalo’s grade
River and rain flooding is 79% of the building damage FEMA expects in Waimanalo, and Waimanalo’s rate of river and rain flooding damage is higher than 88% of U.S. census tracts. Tsunamis add 5%, at a rate in the top 1% of U.S. census tracts.
C− #8 of 93 in Hawaii; higher expected damage per building than 84% of U.S. towns (21,298).
All of Waimanalo’s residents live in one census tract; the figures are that tract’s.
The typical Hawaii town has higher expected damage than 96% of U.S. towns; within the state, Waimanalo has less expected damage per building than 92% of Hawaii towns.
In dollars, FEMA expects about $1.6M a year in losses across Waimanalo: $1.3M to buildings, the rest to people and crops.
Does Waimanalo flood? Sometimes: 21 flood claims since 1980
Every paid claim on a federal flood insurance policy in Waimanalo, from FEMA’s records: 13.7 per 1,000 homes, more than 79% of the 13,809 U.S. towns with a flood insurance record.
Waimanalo 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.5 federal disasters brought FEMA money to Waimanalo
Disasters that paid out in Waimanalo itself (aid to households or repair grants to Waimanalo), newest first, with that year’s flood claims.
- 2026Severe Storms, Flooding, Landslides, and Mudslides41 households applied for aid$215K aid approved
- 2023Wildfires and High Winds2 households applied for aid$700 aid approved
- 2018Severe Storms, Flooding, Landslides, and Mudslides15 households applied for aid$34K aid approved10 flood claims paid that year
- 2008Severe Storms and Flooding16 households applied for aid$42K aid approved
- 2006Severe Storms, Flooding, Landslides, and Mudslides11 households applied for aid$37K aid approved3 flood claims paid 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 Waimanalo after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Waimanalo archive →Waimanalo and its neighbors
Waimanalo has the lowest expected damage per building of the 3 graded towns here. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Waimanalo | C−more damage than 84% | river and rain flooding | 21 |
| Kailua | Dmore damage than 93% | river and rain flooding | 257 |
| Waimanalo Beach | Dmore damage than 94% | river and rain flooding | 2 |
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 Waimanalo 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.
- 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.
- 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 Waimanalo
Is Waimanalo at risk for natural disasters?
On FEMA’s National Risk Index, Waimanalo has higher expected damage per building than 84% of U.S. towns: C− for hazard risk, #8 of 93 in Hawaii. Most of the expected damage is river and rain flooding (79%) and earthquakes (11%). 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 Waimanalo flood?
Flood insurance has paid 21 claims in Waimanalo since 1980, $368K in all, or 13.7 per 1,000 homes, more than 79% of U.S. towns with a flood insurance record.
Is Waimanalo 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 Waimanalo?
FEMA’s Community Rating System list shows no discount for Waimanalo’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 Waimanalo?
By FEMA money that reached Waimanalo, Severe Storms, Flooding, Landslides, and Mudslides (2026): 41 households applied for aid, $215K approved.
Is Waimanalo at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (79%), and Waimanalo’s rate for it is higher than 88% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Waimanalo.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Waimanalo’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.