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UnalaskaAlaskaPhoto: Wanetta Ayers · Public domain
D−Hazard risk
Natural hazards in Unalaska · FEMA

FEMA expects more hazard damage per building in Unalaska than almost anywhere in the U.S., led by tsunamis

On FEMA’s National Risk Index, Unalaska gets a D− for hazard risk: among the highest expected damage per building of U.S. towns. Most of that expected damage is tsunamis (45%), then earthquakes (39%). FEMA’s files show no paid flood insurance claims here.

Tsunamis 45%Earthquakes 39%Volcanic activity 16%

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

among the highestof U.S. townsLess damageMoreExpected yearly damage per dollar of building, vs. the 21,298 U.S. towns we grade
Hazard risk
D−#41 of 41
in Alaska · among the highest of U.S. towns
Main hazard
Tsunamis
45% of expected building damage
Flood claims
0
paid since 1978 · $0
Disasters paid out here
0
of 4 declared for its 2 counties
By hazard

What Unalaska faces

Each hazard’s share of the building damage FEMA expects here, and how its rate compares with the rest of the country.

Tsunamis

45%of expected building damage
Well above average · in the top 1% of U.S. census tracts

Earthquakes

39%of expected building damage
Well above average · in the top 2% of U.S. census tracts

Volcanic activity

16%of expected building damage
Well above average · in the top 1% of U.S. census tracts
Smaller shares here
 Landslides top 1% Winter storms Tornadoes Ice storms Lightning
FEMA models no building damage here
River and rain floodingCoastal floodingHurricanesHailStrong windWildfireCold wavesHeat wavesAvalanches
People, not buildings.Counting harm to people as well as buildings, FEMA’s model puts volcanic activity at 27% of Unalaska’s expected losses. Volcanic activity does little damage to buildings (15.6%), so they aren’t part of the grade.

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. 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.

Check a specific address on FEMA’s flood map, and ask about flood insurance before you buy.
Hazard risk grade

What’s behind Unalaska’s grade

Tsunamis are 45% of the building damage FEMA expects in Unalaska, and Unalaska’s rate of tsunamis damage is in the top 1% of U.S. census tracts. Earthquakes add 39%, at a rate in the top 2% of U.S. census tracts.

Where Unalaska sits
Unalaska
Least damageMiddleMost damage

D− #41 of 41 in Alaska; among the highest expected damage per building of U.S. towns (21,298).

All of Unalaska’s residents live in one census tract; the figures are that tract’s.

What drives the damage to buildings
Tsunamis45%Earthquakes39%Volcanic activity16%Everything else1%

The typical Alaska town has higher expected damage than 93% of U.S. towns; within the state, Unalaska has more expected damage per building than 100% of Alaska towns.

In dollars, FEMA expects about $11.5M a year in losses across Unalaska: $7.6M to buildings, the rest to people and crops.

Shared tract.All of Unalaska’s 4,254 residents (2020 census) live in one census tract. FEMA publishes its model by tract, so the rate and the hazard mix are the tract’s. The flood claims below are the town’s own.
A shared figure. The grade describes the whole tract, not each street in it, and FEMA’s model is an average year for today’s buildings, not a record: the claims below are the record.

How TownRatings grades hazard risk →

Flood insurance claims

Does Unalaska flood? No paid flood claims on record

FEMA’s records show no paid flood insurance claims in Unalaska. That’s not a promise: most homes don’t carry flood insurance, so small floods go unrecorded.

Disasters

The storms Unalaska remembers

None of the 4 disasters declared for its 2 counties shows FEMA aid or repair money reaching Unalaska itself in FEMA’s records, so these are its biggest flood-claim years.

Disasters declared, by decade
Paid out in Unalaskaits 2 counties only

Its 2 counties have had 4 natural disasters declared by the President since 1953, most often severe storms, then floods.

Be ready

Get ready for what Unalaska faces

A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.

Tsunamis
  • 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.
More from Ready.gov ↗
Earthquakes
  • Drop, cover and hold on.
  • Strap tall furniture and the water heater to the wall.
  • Know how to shut off the gas.
More from Ready.gov ↗
Volcanic activity
  • Keep N95 masks and goggles for ash.
  • Know the evacuation routes.
  • Keep ash out of the house and car vents.
More from Ready.gov ↗
Before you buy or rent
  • 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.
When a storm is coming
Forecast and alertsWeather →911, the nearest ERSafety →

Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.

Questions about natural hazards in Unalaska

Is Unalaska at risk for natural disasters?

On FEMA’s National Risk Index, Unalaska has among the highest expected damage per building of U.S. towns: D− for hazard risk. Most of the expected damage is tsunamis (45%) and earthquakes (39%). 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.

Is Unalaska 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.

How much is flood insurance in Unalaska?

FEMA’s Community Rating System list shows no discount for Unalaska’s flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.

Is Unalaska at risk from tsunamis?

It is the largest share of the building damage FEMA expects here (45%), and Unalaska’s rate for it is in the top 1% of U.S. census tracts.

Storm stories

Memories, warnings and help from neighbors in Unalaska.

Town Square →
Start the conversation

Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Unalaska’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.