Hawaii County, HI: home risks and climate
FEMA’s National Risk Index rates Hawaii County “Relatively High” for overall risk relative to other US counties, 2nd of 5 counties in Hawaii by risk score. The hazards rated Relatively High or Very High here are volcanic activity, lightning, earthquake, inland flooding and wildfire. These are relative ratings, not probabilities.
Hawaii County, HI
- Use surge protection for electronics; ask an electrician about a whole-home surge protector.
- Keep trees near the house healthy and trimmed.
- Unplug sensitive electronics before a storm if you can.
- Know if you are in a lahar or ashfall zone.
- Keep N95 masks and goggles for ash.
- Have a plan to protect the HVAC system from ash.
- Look up your FEMA flood zone, and remember that "minimal hazard" zones still flood.
- Raise or move valuables, the furnace and the water heater off a basement floor where you can.
- Test the sump pump and its backup before the wet season.
- Clear dead leaves and needles from gutters, the roof and under decks.
- Keep the first 5 feet around the house free of anything that burns (mulch, firewood, plants).
- Cover vents with 1/8-inch metal mesh to keep embers out.
- Strap the water heater to the wall with two straps.
- Secure tall furniture and TVs to studs.
- Know how to shut off gas at the meter, and only do it if you smell gas.
- Find out whether your home is in a tsunami hazard zone.
- Know the walking route to high ground.
- Strong shaking near the coast means move to high ground now.
- Fit storm shutters or pre-cut, labeled plywood panels and store the fasteners with them.
- Photograph every room and your roof before the season starts, for your insurance file.
- Know your evacuation zone and where you would go.
- Check your FEMA flood zone at your address; V and coastal A zones carry wave risk.
- Know your evacuation route and zone before a storm is named.
- Keep a flood-insurance policy in force; there is usually a 30-day wait.
- Watch for new cracks in the ground, tilting trees or fences, and doors that stick.
- Keep gutters and drains directing water away from slopes.
- Know the signs of a debris flow during heavy rain.
- Pick the safe room: lowest floor, interior, no windows. Tell everyone in the house.
- Keep shoes, a flashlight and a helmet for each person there.
- Turn on wireless emergency alerts on every phone.
- Trim dead or overhanging branches before storm season.
- Check that gutters, siding and roof edges are fastened tight.
- Tie down or store outdoor furniture, grills and trampolines.
- Photograph the roof and siding now, so you have a dated before picture.
- Ask about impact-rated (UL 2218 Class 4) shingles when the roof is replaced.
- Know your policy’s wind and hail deductible in dollars.
- Know where the main water shutoff is and that it turns.
- Insulate pipes in unheated crawlspaces, garages and exterior walls.
- Have the heating system checked before winter.
- Clean gutters so melting snow drains instead of forming ice dams.
- Check attic insulation and air sealing; warm attics cause ice dams.
- Keep a snow shovel, ice melt and a backup heat plan.
- Trim limbs that could fall on the house or the service drop.
- Plan for a multi-day power outage: heat, water, phone charging.
- If you own a generator, know how to run it outdoors safely.
- Watch for new cracks in foundations, walls and door frames; drought shrinks clay soils.
- Fix running toilets and dripping faucets.
- If you have a well, know its depth and recent yield.
Winterize outdoor faucets before ~Dec 1. Typical first 32°F night (50% date) at Mauna Loa 5 Nne, 10 km away. Last freeze ~Apr 12.
Radon Zone 3: lowest predicted indoor radon. EPA recommends testing every home, whatever the zone.
- This weekBefore the first freeze (~Dec 1): disconnect hoses and drain outdoor faucets.
- This monthPress the test button on every smoke and CO alarm.
- This monthCheck the date on the back of every smoke and CO alarm.
- This monthLook under every sink and around toilets and the water heater for drips.
- This monthClean gutters and downspouts after the leaves are down.
- WatchLook in the attic with a flashlight after the first big storm of the season.
What the records say
Plain-language summary of the numbers below, compared with Hawaii and the US.
By FEMA’s hazard scores (0 to 100, the share of US counties scoring lower), volcanic activity scores 100.0, lightning scores 97.6 and earthquake scores 99.1 in Hawaii County, and modeled expected annual losses from all hazards come to about $365.0 million a year across 200,469 residents.
There have been 35 federal disaster declarations covering Hawaii County in the OpenFEMA record, above the Hawaii county median of 25 and above the national county median of 20; 17 came in the last ten years. The most recent was hurricane lala (2026-10-07).
Hawaii County is part of the Hilo-Kailua, HI micropolitan area.
Flood-insurance (NFIP) records list 800 claims in Hawaii County, below the Hawaii county median of 1,157, 85 of them in the last ten years. Of claims with a recorded zone, 21% were outside the mapped high-risk flood zone.
Hawaii County sits in climate zone 1A (very hot-humid) in the hot-humid Building America region and EPA radon zone 3.
At Mauna Loa 5 Nne (10 km from the county’s center), the typical first 32°F night is around Dec 1 and the last around Apr 12 (50% dates, 1991–2020), which sets when to winterize outdoor faucets.
All 18 hazards
FEMA National Risk Index December 2025. Ratings and scores are relative to other US counties, not probabilities. Expected annual loss is FEMA’s modeled average across buildings, people and agriculture.
| Hazard | Risk rating | Risk score | Expected annual loss | Recorded events | Prepare |
|---|---|---|---|---|---|
| Volcanic activity | Very High | 100.0 | $26.3M | 5 | Checklist |
| Lightning | Very High | 97.6 | $2.4M | 966,223 | Checklist |
| Earthquake | Relatively High | 99.1 | $121.3M | — | Checklist |
| Inland flooding | Relatively High | 98.9 | $185.3M | 158 | Checklist |
| Wildfire | Relatively High | 98.3 | $14.1M | — | Checklist |
| Tsunami | Relatively Moderate | 86.2 | $14.9M | 147 | Checklist |
| Landslide | Relatively Low | 84.1 | $23,175 | — | Checklist |
| Hurricane | Relatively Low | 68.3 | $447,385 | 8 | Checklist |
| Coastal flooding | Relatively Low | 50.8 | $125,380 | — | Checklist |
| Drought | Very Low | 27.6 | $15,774 | 3,318 | Checklist |
| Ice storm | Very Low | 7.6 | $3,321 | 0 | Checklist |
| Tornado | Very Low | 7.4 | $33,455 | 4 | Checklist |
| Hail | Very Low | 4.3 | $8,369 | 0 | Checklist |
| Cold wave | Very Low | 2.9 | $14 | 0 | Checklist |
| Strong wind | Very Low | 2.6 | $11,312 | 1 | Checklist |
| Winter weather | Very Low | 1.7 | $504 | 32 | Checklist |
| Heat wave | No Rating | 0.0 | $0 | 0 | Checklist |
| Avalanche | Not Applicable | — | — | — | Checklist |
Federal disaster declarations
Each county-level declaration in OpenFEMA DisasterDeclarationsSummaries v2, counted once per disaster number.
| Declared | Event | Type |
|---|---|---|
| 2026-10-07 | Hurricane Lala | DR · Hurricane |
| 2026-09-25 | Tropical storm Nolo | EM · Tropical Storm |
| 2026-09-01 | Earthquake | DR · Earthquake |
| 2026-08-25 | Hurricane Lala | EM · Tropical Storm |
| 2026-07-26 | Kawaihae road fire | FM · Fire |
| 2026-04-07 | Severe storms, flooding, landslides, and mudslides | DR · Flood |
| 2023-08-10 | Wildfires and high winds | DR · Fire |
| 2023-08-09 | Mauna kea beach fire | FM · Fire |
| 2023-08-08 | Kohala ranch fire | FM · Fire |
| 2021-08-01 | Mana road fire | FM · Fire |
| 2020-07-25 | Hurricane Douglas | EM · Hurricane |
| 2020-04-01 | COVID-19 pandemic | DR · Biological |
Showing the 12 most recent of 35.
Flood-insurance claims (NFIP)
Claims filed under the National Flood Insurance Program, from FEMA’s NfipClaims v3 dataset (all years on file), by year of loss.
Inside vs outside the mapped high-risk zone
By the rated flood zone recorded on each claim. Claims outside the high-risk zone are a reminder that “minimal hazard” is not “no hazard”. Check your own zone with an address in the Snapshot.
Climate, radon and freeze
This month’s plan for Hawaii County
Region tasks plus this county’s hazard ratings and freeze dates. Add your ZIP and systems on the Home Plan page to subscribe in your calendar.
November7 tasks
- This weekBefore the first freeze (~Dec 1): disconnect hoses and drain outdoor faucets.
Water left in a hose bib can freeze, split the pipe inside the wall, and only leak when you turn it on in spring.
How
Remove hoses, close the indoor shutoff valve for each outdoor faucet if you have one, and open the outside faucet to drain it.
- This monthPress the test button on every smoke and CO alarm.
An alarm you have not heard in months may have a dead battery or sensor. NFPA recommends testing smoke alarms at least once a month.
How
Hold the test button until it sounds. Anything silent or chirping: replace the battery, or the whole alarm if it is past its date.
- This monthCheck the date on the back of every smoke and CO alarm.
Smoke alarms wear out: NFPA advises replacing them 10 years after the manufacture date. CO alarms have their own end-of-life date printed on them.
How
Twist each alarm off its base and read the date. Replace any past its life; swap batteries in alarms that take them.
- This monthLook under every sink and around toilets and the water heater for drips.
Slow leaks rot cabinets and subfloors long before they show. Catching one early is a washer, not a floor.
How
Use a flashlight: feel supply lines and the shutoff valves, look for stains, warped cabinet floors or a toilet that rocks.
- This monthClean gutters and downspouts after the leaves are down.
Blocked gutters overflow at the foundation, rot fascia and, in cold climates, help ice dams form.
How
From a stable ladder (with a helper), scoop debris, then flush each downspout with a hose. Extensions should drop water 4 to 6 feet from the house.
- WatchLook in the attic with a flashlight after the first big storm of the season.
Stains on the roof deck, wet insulation or daylight around vents show leaks early, and droppings show pests.
How
Stay on the joists. Look around chimneys, vent pipes and valleys, the places most leaks start.
- WatchRun the heat once before you need it; book a check if it has been a year.
Heating sits idle for most of the year in warm climates and cold snaps arrive fast. A short test run finds problems while repairs are easy to book.
How
Switch to heat, raise the setpoint a few degrees and confirm warm air within a few minutes. A brief dusty smell is normal.
December3 tasks
- This monthPress the test button on every smoke and CO alarm.
An alarm you have not heard in months may have a dead battery or sensor. NFPA recommends testing smoke alarms at least once a month.
How
Hold the test button until it sounds. Anything silent or chirping: replace the battery, or the whole alarm if it is past its date.
- WatchDegrease the range-hood filter.
Grease-clogged hood filters stop pulling smoke and grease out of the kitchen and can feed a stovetop fire.
How
Pop the metal filter out and soak it in hot water with dish soap and baking soda, or run it through the dishwasher if the maker allows.
- WatchReset sprinkler schedules for the cool season and test the rain sensor.
Lawns need far less water in winter; overwatering wastes water and keeps foundations wet.
How
Cut run times, check each zone for broken heads, and press the rain sensor test if it has one.
Information, not insurance, legal or engineering advice. Ratings describe the county as a whole; your address can differ. Found an error? Send a correction.