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Delaware County, Iowa

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

Relatively Low overall risk
26th of 99highest risk in Iowa
$17Mexpected losses a year
16federal declarations
1 in 143homes with flood insurance
Photo: U.S. Geological Survey, public domain

Delaware County, Iowa has a relatively low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is lower than 50% of US counties. It ranks 26th of 99 counties in Iowa. The costliest hazards here are inland flooding, tornadoes and hail. FEMA estimates about $17 million a year in expected losses, or roughly $975 per resident. Since 1968 it has been included in 16 federal disaster or emergency declarations for natural events (15 major disasters). The most recent was in August 2018 (severe storms, tornadoes, straight-line winds and flooding). Fewer than 1 in 100 homes here carry federal flood insurance (66 policies). Since 1978, federal flood insurance has paid about $4.1 million on 105 claims here, including $1.5 million for floods in 2010.

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

Top risks in Delaware County

$10.2 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.
$1.8 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.

Hail

Moderate
$1.4 million a yearExpected losses. Damaging events about 5 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 floodingLow61.7
$10M
TornadoLow58.5
$2M
HailModerate86.4
$1M
Cold waveLow54.9
$1M
DroughtModerate81.0
$1M
Strong windModerate70.0
$1M
Heat waveVery Low34.0
$179K
LightningLow28.1
$107K
Winter weatherLow42.5
$53K
EarthquakeVery Low24.6
$46K
Ice stormLow28.7
$31K
HurricaneVery Low19.4
$6K
LandslideLow67.9
$5K
WildfireVery Low12.4
$4K

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 Delaware County. 2020s bar runs to November 2026.

By type

Flood8
Severe Storm7
Hurricane1

Most recent

Aug 20, 2018Severe Storms, Tornadoes, Straight-Line Winds, and FloodingMajor disaster
Oct 31, 2016Severe Storms and FloodingMajor disaster
Jul 31, 2013Severe Storms, Tornadoes, and FloodingMajor disaster
Jul 2, 2013Severe Storms, Tornadoes, and FloodingMajor disaster
Jul 29, 2010Severe Storms, Flooding, and TornadoesMajor disaster
May 27, 2008Severe Storms, Tornadoes, and FloodingMajor disaster
Sep 10, 2005Hurricane Katrina EvacuationEmergency
May 25, 2004Severe Storms, Tornadoes, and FloodingMajor disaster
Jun 19, 2002Severe Storms and FloodingMajor disaster
May 21, 1999Severe Storms, Flooding, and TornadoesMajor disaster
Show all 16
Jul 2, 1998Severe Storms, Tornadoes and FloodingMajor disaster
Jul 9, 1993Severe Storms & FloodingMajor disaster
Jun 24, 1974Severe Storms & FloodingMajor disaster
Sep 26, 1972Severe Storms & FloodingMajor disaster
Aug 14, 1969Heavy Rains & FloodingMajor disaster
Aug 4, 1968Heavy Rains & FloodingMajor disaster

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

Storm history since 1955

Tornado risk by county ›

The National Weather Service has logged 466 storm reports in Delaware County since 1955, with 0 deaths and 22 injuries and about $97.2 million in reported damage. The strongest on record here was an F4 tornado on March 13, 1990.

40tornadoes
152hail reports, largest 4.5 inches
223damaging thunderstorm winds
40floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
Mar 13, 1990F4–0 / 0
Aug 12, 1974F4–12 / 0
Jul 12, 1971F3–2 / 0
Nov 15, 1960F2–0 / 0
May 4, 1964F2–2 / 0

Most damaging storms

DateTypeNearDamage
Jul 23, 2010FloodBackbone State Park$26M
Mar 13, 1990Tornado–$25M
Jul 24, 2010Flash FloodManchester Arpt$25M
Jun 1, 2008FloodBackbone State Park$4M
May 17, 2000HailManchester$4M
Jul 12, 1971Tornado–$3M

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 Delaware County

Check your address flood zone ›
0.7%of homes have federal flood insurance (66 policies)
6.4%of homes in mapped high-risk flood zones are insured
$4.1 millionpaid on 105 flood claims since 1978
2010costliest year, with $1.5 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 Delaware County

$177,900median home value (Iowa $208,000, US $332,700)
1967median year homes were built (Iowa 1972, US 1980)
66%of homes built before 1980, before many modern wind, quake and flood building rules
2.9%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; 8,169 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
Linn CountyModerate21
Dubuque CountyLow19
Jones CountyVery Low20
Buchanan CountyVery Low23
Fayette CountyLow20
Clayton CountyVery Low25

Common questions about Delaware County

What is the biggest natural hazard in Delaware County?

Inland flooding has the highest expected yearly losses in Delaware County, about $10.2 million a year in FEMA's estimate. Tornado is second at $1.8 million.

How many federal disasters has Delaware County had?

Delaware County has been included in 16 federal disaster or emergency declarations for natural events since 1968, including 15 major disasters. The most recent was Severe Storms, Tornadoes, Straight-Line Winds, and Flooding in August 2018.

Is Delaware County a high-risk place to live?

Its overall rating is Relatively Low, 26th 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 Delaware County?

Standard home insurance does not cover flooding. About 1 in 143 homes in Delaware 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 Delaware County had?

NOAA records list 40 tornadoes in Delaware County since 1950. The strongest was an F4 tornado on March 13, 1990. The weather service has also logged 152 hail reports and 40 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.