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Hamilton County, Iowa

Natural disaster risk, federal disaster history and flood insurance facts.

Relatively Low overall risk
35th of 99highest risk in Iowa
$16Mexpected losses a year
19federal declarations
1 in 1000homes with flood insurance
Photo: U.S. Geological Survey, public domain

Hamilton County, Iowa has a relatively low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is lower than 57% of US counties. It ranks 35th of 99 counties in Iowa. The costliest hazards here are inland flooding, drought and tornadoes. FEMA estimates about $16 million a year in expected losses, or roughly $1,031 per resident. Since 1965 it has been included in 19 federal disaster or emergency declarations for natural events (18 major disasters). The most recent was in May 2024 (severe storms, tornadoes and flooding). Only 6 homes here carry federal flood insurance. Since 1978, federal flood insurance has paid about $189,000 on 28 claims here.

FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.

Top risks in Hamilton County

$5.8 million a yearExpected losses. Damaging events about 2 times a year.
  • Check the FEMA flood map for your address, and ask the seller or landlord about past flooding.
  • Price a flood policy now. Most new federal policies take 30 days to start.
$3.7 million a yearExpected losses. Damaging events about 11 times a year.
  • Check local water restrictions.
  • Choose drought-tolerant plants.
$2.4 million a yearExpected losses. Damaging events about once every 2 years.
  • Pick a shelter spot: a basement, or an inside room on the lowest floor with no windows.
  • Turn on emergency alerts on your phone and keep a weather radio.
HazardRatingScoreExpected loss a year
Inland floodingLow41.0
$6M
DroughtHigh96.3
$4M
TornadoLow64.8
$2M
Cold waveLow58.5
$2M
Strong windModerate68.8
$1M
HailLow72.3
$712K
Winter weatherModerate66.1
$129K
LightningVery Low17.5
$69K
Ice stormLow39.2
$58K
EarthquakeVery Low17.1
$25K
Heat waveVery Low10.7
$23K
HurricaneVery Low18.9
$6K
WildfireVery Low13.5
$5K
LandslideVery Low33.6
$467

Scores are percentiles: a score of 90 means higher risk than about 90% of US counties for that hazard. Hazards FEMA does not rate here are left out. Social vulnerability is relatively low and community resilience is relatively high in FEMA's measures.

Federal disaster history

Recent disasters nationwide ›

Declarations by decade

Federal declarations for natural events that included Hamilton County. 2020s bar runs to November 2026.

By type

Severe Storm9
Flood7
Tornado1
Severe Ice Storm1
Hurricane1

Most recent

May 24, 2024Severe Storms, Tornadoes, and FloodingMajor disaster
Feb 23, 2022Severe Storms, Straight-Line Winds, and TornadoesMajor disaster
Mar 23, 2019Severe Storms and FloodingMajor disaster
Aug 20, 2018Severe Storms, Tornadoes, Straight-Line Winds, and FloodingMajor disaster
Aug 5, 2014Severe Storms, Tornadoes, Straight-Line Winds, and FloodingMajor disaster
Jul 29, 2010Severe Storms, Flooding, and TornadoesMajor disaster
May 27, 2008Severe Storms, Tornadoes, and FloodingMajor disaster
Mar 14, 2007Severe Winter StormsMajor disaster
Sep 10, 2005Hurricane Katrina EvacuationEmergency
May 25, 2004Severe Storms, Tornadoes, and FloodingMajor disaster
Show all 19
Jul 2, 1998Severe Storms, Tornadoes and FloodingMajor disaster
Aug 21, 1996Severe Storms, and FloodingMajor disaster
Jul 9, 1993Severe Storms & FloodingMajor disaster
Dec 26, 1991Ice StormMajor disaster
Jul 12, 1991Severe Storms & FloodingMajor disaster
May 26, 1990Severe Storms & FloodingMajor disaster
Jul 1, 1979High Winds & TornadoesMajor disaster
Aug 14, 1969Heavy Rains & FloodingMajor disaster
Apr 22, 1965FloodingMajor disaster

Iowa also had 11 statewide declarations that did not name single counties.

Storm history since 1963

Tornado risk by county ›

The National Weather Service has logged 420 storm reports in Hamilton County since 1963, with 2 deaths and 17 injuries and about $70.7 million in reported damage. The strongest on record here was an F4 tornado on May 24, 1989.

56tornadoes
149hail reports, largest 2.75 inches
134damaging thunderstorm winds
42floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
May 24, 1989F4–0 / 0
Nov 12, 2005F3Stratford3 / 1
Mar 13, 1990F2–0 / 0
Jun 22, 1974F2–0 / 0
Jun 28, 1979F2–10 / 0

Most damaging storms

DateTypeNearDamage
May 24, 1989Tornado–$25M
Jun 12, 2010FloodHighview$20M
Nov 12, 2005TornadoStratford$12M
Mar 13, 1990Tornado–$3M
Jul 8, 1995HailEllsworth$1M
Jun 24, 2010FloodWebster City$1M

Source: NOAA Storm Events Database, county-based reports through Sep 22, 2025. Tornado records start in 1950, hail and wind in 1955, and floods and other storm types in 1996, so older decades undercount. Damage is in dollars of the year it happened and is often an estimate. Winter storms, heat and hurricanes are logged by forecast zone, not county, so they are not counted here.

Flood insurance in Hamilton County

Check your address flood zone ›
0.1%of homes have federal flood insurance (6 policies)
1.8%of homes in mapped high-risk flood zones are insured
$189,455paid on 28 flood claims since 1978
2010costliest year, with $108,500 paid

National Flood Insurance Program (NFIP) records only; private flood policies are not included. Home counts as of Aug 3, 2026. Since 2021 NFIP prices each home separately under Risk Rating 2.0, so your price depends on the building, not the county. Ask an agent for a quote.

Homes in Hamilton County

$156,400median home value (Iowa $208,000, US $332,700)
1953median year homes were built (Iowa 1972, US 1980)
79%of homes built before 1980, before many modern wind, quake and flood building rules
1.6%of homes are mobile homes, which are the least safe in tornadoes and high winds

Older homes and mobile homes usually suffer more damage in storms, floods and earthquakes, and can cost more to insure. If you are buying, ask about roof age, foundation bolting and any retrofits. Source: US Census Bureau, American Community Survey 2020 to 2024 5-year estimates; 7,040 housing units.

Compare in Iowa

All 99 ›
Largest countiesOverall riskTop hazard
Polk CountyModerateInland flooding
Linn CountyModerateInland flooding
Scott CountyModerateInland flooding
Johnson CountyModerateTornado
Black Hawk CountyLowInland flooding
Woodbury CountyModerateInland flooding
Dallas CountyLowInland flooding
Dubuque CountyLowInland flooding

Neighboring counties

CountyOverall riskDeclarations
Story CountyLow20
Webster CountyLow18
Boone CountyVery Low15
Hardin CountyLow16
Wright CountyVery Low22
Franklin CountyVery Low20

Common questions about Hamilton County

What is the biggest natural hazard in Hamilton County?

Inland flooding has the highest expected yearly losses in Hamilton County, about $5.8 million a year in FEMA's estimate. Drought is second at $3.7 million.

How many federal disasters has Hamilton County had?

Hamilton County has been included in 19 federal disaster or emergency declarations for natural events since 1965, including 18 major disasters. The most recent was Severe Storms, Tornadoes, and Flooding in May 2024.

Is Hamilton County a high-risk place to live?

Its overall rating is Relatively Low, 35th highest of 99 in Iowa. A county rating covers the whole area. Risk at one address can be much higher or lower, so check the FEMA flood map and ask about the home's history.

Do I need flood insurance in Hamilton County?

Standard home insurance does not cover flooding. About 1 in 1000 homes in Hamilton County has federal flood insurance. Lenders require it in mapped high-risk zones, but many flood claims come from outside those zones.

How many tornadoes has Hamilton County had?

NOAA records list 56 tornadoes in Hamilton County since 1950. The strongest was an F4 tornado on May 24, 1989. The weather service has also logged 149 hail reports and 42 floods here.

Sources: FEMA National Risk Index (December 2025), OpenFEMA Disaster Declarations Summaries, and NFIP policy and claims data. Hazard Compass is independent and not affiliated with FEMA. These figures describe the whole county, not a single property, and are not insurance or safety advice. Report a problem.