Harrison County, Iowa
Natural disaster risk, federal disaster history and flood insurance facts.
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
- 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.
- 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.
- Check local water restrictions.
- Choose drought-tolerant plants.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Inland flooding | 37.0 | $4M | ||
| Tornado | 60.1 | $2M | ||
| Drought | 86.4 | $1M | ||
| Hail | 86.4 | $1M | ||
| Strong wind | 55.9 | $627K | ||
| Cold wave | 29.1 | $379K | ||
| Ice storm | 53.7 | $96K | ||
| Wildfire | 59.8 | $80K | ||
| Heat wave | 19.4 | $56K | ||
| Lightning | 16.4 | $55K | ||
| Winter weather | 36.0 | $37K | ||
| Landslide | 84.6 | $27K | ||
| Earthquake | 11.8 | $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
Most recent
Show all 22
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.
Strongest tornadoes
| Date | Strength | Near | Hurt / killed |
|---|---|---|---|
| May 16, 1999 | F3 | Missouri Vly | 16 / 2 |
| Jun 16, 1992 | F3 | – | 0 / 0 |
| May 16, 1999 | F3 | Missouri Vly | 0 / 0 |
| May 6, 1983 | F2 | – | 0 / 0 |
| Sep 12, 1972 | F2 | – | 0 / 0 |
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| May 5, 2007 | Flash Flood | Missouri Vly | $15M |
| Aug 1, 2011 | Flood | River Sioux | $7M |
| Jun 16, 1992 | Tornado | – | $3M |
| Mar 13, 2019 | Flood | Dunlap | $2M |
| May 16, 1999 | Tornado | Missouri Vly | $2M |
| Apr 14, 1994 | Thunderstorm Wind | Mondamin | $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 ›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
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 counties | Overall risk | Top hazard |
|---|---|---|
| Polk County | Inland flooding | |
| Linn County | Inland flooding | |
| Scott County | Inland flooding | |
| Johnson County | Tornado | |
| Black Hawk County | Inland flooding | |
| Woodbury County | Inland flooding | |
| Dallas County | Inland flooding | |
| Dubuque County | Inland flooding |
Neighboring counties
| County | Overall risk | Declarations |
|---|---|---|
| Pottawattamie County | 24 | |
| Washington County, NE | 22 | |
| Crawford County | 21 | |
| Shelby County | 18 | |
| Monona County | 18 | |
| Burt County, NE | 18 |
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.