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Iona IdahoPhoto: Sociotard · CC BY 3.0
B−Hazard risk
Natural hazards in Iona · FEMA

FEMA expects about as much hazard damage per building in Iona as in the typical U.S. town, mostly from river and rain flooding

On FEMA’s National Risk Index, Iona gets a B− for hazard risk: lower expected damage per building than 54% of U.S. towns, #26 of 59 in Idaho. Most of that expected damage is river and rain flooding (75%), then earthquakes (18%). FEMA’s files show no paid flood insurance claims here.

River and rain flooding 75%Earthquakes 18%Hail 5%

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

less than 54%of U.S. townsLess damageMoreExpected yearly damage per dollar of building, vs. the 21,298 U.S. towns we grade#26 of 59 in Idaho
Hazard risk
B−#26 of 59
in Idaho · lower than 54% of U.S. towns
Main hazard
River and rain flooding
75% of expected building damage
Flood claims
0
paid since 1978 · $0
Disasters paid out here
0
of 3 declared for Bonneville County
By hazard

What Iona 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

75%of expected building damage
About average · higher than 58% of U.S. census tracts
Recorded about once every 2 years in the area

Earthquakes

18%of expected building damage
Well above average · higher than 80% of U.S. census tracts
Smaller shares here
 Hail Tornadoes Strong wind Wildfire Ice storms Cold waves Lightning Winter storms Heat waves Landslides Volcanic activity top 4%
FEMA models no building damage here
Coastal floodingHurricanesAvalanchesTsunamis
People, not buildings.Counting harm to people as well as buildings, FEMA’s model puts cold waves at 27% of Iona’s expected losses. Cold waves do little damage to buildings (0.1%), 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. 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.

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

What’s behind Iona’s grade

River and rain flooding is 75% of the building damage FEMA expects in Iona, and Iona’s rate of river and rain flooding damage is higher than 58% of U.S. census tracts. Next is earthquakes at 18% (higher than 80% of U.S. census tracts).

Where Iona sits
Iona
Least damageMiddleMost damage

B− #26 of 59 in Idaho; lower expected damage per building than 54% of U.S. towns (21,298).

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

What drives the damage to buildings
River and rain flooding75%Earthquakes18%Hail5%Everything else2%

The typical Idaho town has higher expected damage than 52% of U.S. towns; within the state, Iona has less expected damage per building than 57% of Idaho towns.

In dollars, FEMA expects about $996K a year in losses across Iona: $591K to buildings, the rest to people and crops.

Shared tract.All of Iona’s 2,717 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 Iona flood? No paid flood claims on record

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

of all homes are insured
No community discount

Iona isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.

Insurance rates: Bonneville County.
Disasters

The storms Iona remembers

None of the 3 disasters declared for Bonneville County shows FEMA aid or repair money reaching Iona itself in FEMA’s records, so these are its biggest flood-claim years.

Disasters declared, by decade
Paid out in IonaBonneville County only

Bonneville County has had 3 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.

Also 1 FEMA wildfire suppression grant (Fire Management Assistance, not a disaster declaration) for fires in Bonneville County, 2016–2016.

Be ready

Get ready for what Iona faces

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

When the river rises
  • 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.
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 ↗
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 Iona

Is Iona at risk for natural disasters?

On FEMA’s National Risk Index, Iona has lower expected damage per building than 54% of U.S. towns: B− for hazard risk, #26 of 59 in Idaho. Most of the expected damage is river and rain flooding (75%) and earthquakes (18%). 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 Iona 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 Bonneville County, 0.2% of all homes carry federal flood insurance.

How much is flood insurance in Iona?

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

Is Iona at risk from river and rain flooding?

It is the largest share of the building damage FEMA expects here (75%), and Iona’s rate for it is higher than 58% of U.S. census tracts.

Storm stories

Memories, warnings and help from neighbors in Iona.

Town Square →
Start the conversation

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