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Plymouth County, Iowa

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

Relatively Low overall risk
29th of 99highest risk in Iowa
$18Mexpected losses a year
14federal declarations
1 in 500homes with flood insurance
Photo: U.S. Geological Survey, public domain

Plymouth County, Iowa has a relatively low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is lower than 51% of US counties. It ranks 29th of 99 counties in Iowa. The costliest hazards here are inland flooding, tornadoes and hail. FEMA estimates about $18 million a year in expected losses, or roughly $684 per resident. Since 1965 it has been included in 14 federal disaster or emergency declarations for natural events (11 major disasters). The most recent was in June 2024 (severe storms, flooding, straight-line winds and tornadoes). Only 20 homes here carry federal flood insurance. Since 1978, federal flood insurance has paid about $606,000 on 25 claims here.

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

Top risks in Plymouth County

$6.4 million a yearExpected losses. Damaging events about 3 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.

Tornado

Moderate
$3.8 million a yearExpected losses. Damaging events about once every 1 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.

Hail

Moderate
$2.7 million a yearExpected losses. Damaging events about 6 times a year.
  • Ask about the roof age and any impact-rated shingles.
  • Check your home policy for a separate wind and hail deductible.
HazardRatingScoreExpected loss a year
Inland floodingLow45.2
$6M
TornadoModerate77.4
$4M
HailModerate93.5
$3M
DroughtModerate90.3
$2M
Cold waveLow52.3
$1M
Strong windLow42.9
$499K
Heat waveLow41.7
$278K
Ice stormModerate70.3
$251K
WildfireLow70.5
$200K
Winter weatherModerate75.8
$192K
LightningLow37.2
$162K
LandslideLow81.1
$20K
EarthquakeVery Low14.4
$17K

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 very high in FEMA's measures.

Federal disaster history

Recent disasters nationwide ›

Declarations by decade

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

By type

Flood6
Severe Storm4
Drought1
Severe Ice Storm1
Hurricane1
Snowstorm1

Most recent

Jun 24, 2024Severe Storms, Flooding, Straight-Line Winds, and TornadoesMajor disaster
Mar 23, 2019Severe Storms and FloodingMajor disaster
Jul 24, 2014Severe Storms, Tornadoes, Straight-Line Winds, and FloodingMajor disaster
Jul 2, 2013Severe Storms, Tornadoes, and FloodingMajor disaster
Feb 25, 2010Severe Winter Storms and SnowstormMajor disaster
Mar 30, 2007SnowEmergency
Sep 10, 2005Hurricane Katrina EvacuationEmergency
Aug 21, 1996Severe Storms, and FloodingMajor disaster
Jul 9, 1993Severe Storms & FloodingMajor disaster
Dec 26, 1991Ice StormMajor disaster
Show all 14
May 26, 1990Severe Storms & FloodingMajor disaster
Mar 31, 1977DroughtEmergency
Apr 25, 1969FloodingMajor disaster
Apr 22, 1965FloodingMajor disaster

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

Storm history since 1951

Tornado risk by county ›

The National Weather Service has logged 701 storm reports in Plymouth County since 1951, with 0 deaths and 10 injuries and about $30.3 million in reported damage. The strongest on record here was an F3 tornado on May 5, 1964.

54tornadoes
282hail reports, largest 3.5 inches
228damaging thunderstorm winds
133floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
May 5, 1964F3–0 / 0
Jun 14, 1967F3–3 / 0
May 8, 1964F3–0 / 0
Jun 7, 1965F3–0 / 0
Jun 12, 1994F2–0 / 0

Most damaging storms

DateTypeNearDamage
Jun 22, 2021HailO Leary$5M
Jun 12, 1994Tornado–$5M
May 5, 1964Tornado–$3M
Jul 5, 1978Tornado–$3M
Jun 6, 1980Tornado–$3M
Mar 13, 2019FloodJames$2M

Source: NOAA Storm Events Database, county-based reports through Jul 2, 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 Plymouth County

Check your address flood zone ›
0.2%of homes have federal flood insurance (20 policies)
0%of homes in mapped high-risk flood zones are insured
$605,550paid on 25 flood claims since 1978
2024costliest year, with $351,612 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 Plymouth County

$228,900median home value (Iowa $208,000, US $332,700)
1971median year homes were built (Iowa 1972, US 1980)
63%of homes built before 1980, before many modern wind, quake and flood building rules
3.8%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; 10,891 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
Woodbury CountyModerate16
Sioux CountyLow13
Union County, SDVery Low17
O'Brien CountyVery Low13
Cherokee CountyVery Low21

Cities in Plymouth County

Common questions about Plymouth County

What is the biggest natural hazard in Plymouth County?

Inland flooding has the highest expected yearly losses in Plymouth County, about $6.4 million a year in FEMA's estimate. Tornado is second at $3.8 million.

How many federal disasters has Plymouth County had?

Plymouth County has been included in 14 federal disaster or emergency declarations for natural events since 1965, including 11 major disasters. The most recent was Severe Storms, Flooding, Straight-Line Winds, and Tornadoes in June 2024.

Is Plymouth County a high-risk place to live?

Its overall rating is Relatively Low, 29th 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 Plymouth County?

Standard home insurance does not cover flooding. About 1 in 500 homes in Plymouth 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 Plymouth County had?

NOAA records list 54 tornadoes in Plymouth County since 1950. The strongest was an F3 tornado on May 5, 1964. The weather service has also logged 282 hail reports and 133 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.