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Harrison County, Iowa

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

Very Low overall risk
61st of 99highest risk in Iowa
$10Mexpected losses a year
22federal declarations
1 in 50homes with flood insurance
Photo: U.S. Geological Survey, public domain

Harrison County, Iowa has a very low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is lower than 69% of US counties. It ranks 61st of 99 counties in Iowa. The costliest hazards here are inland flooding, tornadoes and drought. FEMA estimates about $9.8 million a year in expected losses, or roughly $675 per resident. Since 1965 it has been included in 22 federal disaster or emergency declarations for natural events (20 major disasters). The most recent was in May 2025 (severe winter storm). About 1 in 50 homes here carry federal flood insurance (177 policies). Since 1978, federal flood insurance has paid about $3.4 million on 192 claims here, including $1.8 million for floods in 2007.

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

Top risks in Harrison County

$4.2 million a yearExpected losses. Damaging events about once 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.
$1.7 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.

Drought

Moderate
$1.3 million a yearExpected losses. Damaging events about 19 times a year.
  • Check local water restrictions.
  • Choose drought-tolerant plants.
HazardRatingScoreExpected loss a year
Inland floodingLow37.0
$4M
TornadoLow60.1
$2M
DroughtModerate86.4
$1M
HailModerate86.4
$1M
Strong windModerate55.9
$627K
Cold waveLow29.1
$379K
Ice stormLow53.7
$96K
WildfireVery Low59.8
$80K
Heat waveVery Low19.4
$56K
LightningVery Low16.4
$55K
Winter weatherLow36.0
$37K
LandslideLow84.6
$27K
EarthquakeVery Low11.8
$12K

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 moderate 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 Harrison County. 2020s bar runs to November 2026.

By type

Flood9
Severe Storm9
Hurricane1
Snowstorm1
Tornado1
Winter Storm1

Most recent

May 21, 2025Severe Winter StormMajor disaster
Jun 24, 2024Severe Storms, Flooding, Straight-Line Winds, and TornadoesMajor disaster
May 24, 2024Severe Storms, Tornadoes, and FloodingMajor disaster
May 14, 2024Severe Storms and TornadoesMajor disaster
Mar 23, 2019Severe Storms and FloodingMajor disaster
Jun 27, 2011FloodingMajor disaster
Mar 2, 2010Severe Winter StormMajor disaster
Feb 25, 2010Severe Winter Storms and SnowstormMajor disaster
May 27, 2008Severe Storms, Tornadoes, and FloodingMajor disaster
May 25, 2007Severe Storms, Flooding, and TornadoesMajor disaster
Show all 22
Mar 30, 2007SnowEmergency
Sep 10, 2005Hurricane Katrina EvacuationEmergency
Jul 22, 1999Severe Storms and FloodingMajor disaster
May 21, 1999Severe Storms, Flooding, and TornadoesMajor disaster
Jul 2, 1998Severe Storms, Tornadoes and FloodingMajor disaster
Aug 21, 1996Severe Storms, and FloodingMajor disaster
Jul 9, 1993Severe Storms & FloodingMajor disaster
Jun 24, 1974Severe Storms & FloodingMajor disaster
Sep 26, 1972Severe Storms & FloodingMajor disaster
Aug 18, 1972Severe Storms & FloodingMajor disaster
Apr 25, 1969FloodingMajor disaster
Apr 22, 1965FloodingMajor disaster

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

Storm history since 1959

Tornado risk by county ›

The National Weather Service has logged 497 storm reports in Harrison County since 1959, with 2 deaths and 20 injuries and about $31.4 million in reported damage. The strongest on record here was an F3 tornado on May 16, 1999 near Missouri Vly.

34tornadoes
218hail reports, largest 3 inches
210damaging thunderstorm winds
26floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
May 16, 1999F3Missouri Vly16 / 2
Jun 16, 1992F3–0 / 0
May 16, 1999F3Missouri Vly0 / 0
May 6, 1983F2–0 / 0
Sep 12, 1972F2–0 / 0

Most damaging storms

DateTypeNearDamage
May 5, 2007Flash FloodMissouri Vly$15M
Aug 1, 2011FloodRiver Sioux$7M
Jun 16, 1992Tornado–$3M
Mar 13, 2019FloodDunlap$2M
May 16, 1999TornadoMissouri Vly$2M
Apr 14, 1994Thunderstorm WindMondamin$500K

Source: NOAA Storm Events Database, county-based reports through May 31, 2026. 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 Harrison County

Check your address flood zone ›
2%of homes have federal flood insurance (177 policies)
14.2%of homes in mapped high-risk flood zones are insured
$3.4 millionpaid on 192 flood claims since 1978
2007costliest year, with $1.8 million 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 Harrison County

$176,000median home value (Iowa $208,000, US $332,700)
1954median year homes were built (Iowa 1972, US 1980)
72%of homes built before 1980, before many modern wind, quake and flood building rules
4.6%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; 6,698 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
Pottawattamie CountyLow24
Washington County, NEVery Low22
Crawford CountyLow21
Shelby CountyVery Low18
Monona CountyVery Low18
Burt County, NEVery Low18

Common questions about Harrison County

What is the biggest natural hazard in Harrison County?

Inland flooding has the highest expected yearly losses in Harrison County, about $4.2 million a year in FEMA's estimate. Tornado is second at $1.7 million.

How many federal disasters has Harrison County had?

Harrison County has been included in 22 federal disaster or emergency declarations for natural events since 1965, including 20 major disasters. The most recent was Severe Winter Storm in May 2025.

Is Harrison County a high-risk place to live?

Its overall rating is Very Low, 61st 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 Harrison County?

Standard home insurance does not cover flooding. About 1 in 50 homes in Harrison 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 Harrison County had?

NOAA records list 34 tornadoes in Harrison County since 1950. The strongest was an F3 tornado on May 16, 1999 near Missouri Vly. The weather service has also logged 218 hail reports and 26 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.