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Johnson County, Iowa
Recorded hazard history: storm events since 1950, federal disaster declarations since 1953, flood insurance claims since 1978, and FEMA's risk index.
NCEI notes that Storm Data is compiled from a variety of sources including the National Weather Service, other federal, state and local agencies, the media and the public; that property and crop damage figures are estimates; and that some events are recorded by NWS forecast zone rather than by county. FEMA notes that NFIP claim records are redacted and aggregated to protect the privacy of policyholders. NCEI storm records through 30 Jun 2026; OpenFEMA declarations refreshed 1 Oct 2026; NFIP claims as of 8 Sep 2026.
Between 1950 and 2026, NCEI recorded 901 storm events in Johnson County, Iowa, led by damaging wind.
That is 147.0 events per 100 square miles, in line with the Iowa figure of 124.6, and 58.2 per 10,000 residents against 218.0 statewide.
47 events fall in the 12 months to 30 Jun 2026. NCEI attributes 6 deaths and 71 injuries to events in the county, with property damage estimated at $340M and crop damage at $46M.
FEMA has designated the county in 24 federal disaster declarations since 1953; the most recent is Severe Storms (major disaster, 17 Aug 2020).
National Flood Insurance Program policyholders in the county filed 446 claims since 1978, of which 371 were paid, totalling $32M (about $86K per paid claim). FEMA counts 360 residential flood policies in force.
FEMA's National Risk Index rates the county's overall risk as "Relatively Moderate" and its expected annual loss as "Relatively Moderate" ($96M a year across 18 hazards).
1 tropical storm or hurricane track in the HURDAT2 record passed within 100 miles of the county's centre at tropical-storm strength or more, 0 of them within 50 miles at hurricane strength.
Compared with Iowa and the United States
| Measure | Johnson County | Iowa | US |
|---|---|---|---|
| Recorded events since 1950 | 901 | 69,606 | 1,977,440 |
| Events per 100 square miles | 147.0 | 124.6 | 56.0 |
| Events per 10,000 residents | 58.2 | 218.0 | 59.6 |
| Events in the last 12 months | 47 | 1,467 | 62,008 |
| Deaths recorded by NCEI | 6 | 223 | 26,435 |
| Property damage (NCEI estimates) | $340M | $6.5B | $575B |
| NFIP claims per 1,000 residents | 2.9 | 4.6 | 8.1 |
| Average paid NFIP claim | $86K | $30K | $43K |
| Claims per 100 policies in force, last 10 years | 1.1 | 21.8 | 16.1 |
County-recorded events plus zone-recorded events whose forecast zone is named for the county. State and US rows include events recorded only by forecast zone. Rates use 2021 Census population and land area.
Events by decade
Trend: 579 events in the 20 years to 2025 against 216 in the 20 years before. Reporting practice changed in 1996 and again with automated reports in the 2000s, so decade totals measure the record as much as the weather.
Events by type
Hazard pages exist for hail, tornado, flood, wind and winter where the county has at least 10 recorded events. "Other" covers heavy rain, debris flow, dust, funnel clouds and similar reports.
Largest recorded events
| Date | Event type | Group | Magnitude | Property damage | Crop damage | Deaths | Injuries | Geography |
|---|---|---|---|---|---|---|---|---|
| 10 Jan 2023 | Freezing Fog | Fog | — | — | — | 2 | — | Forecast zone |
| 22 May 1962 | Tornado | Tornado | F2 | $250K | — | 1 | — | County |
| 29 May 2011 | Thunderstorm Wind | Wind | 75 mph | $10K | — | 1 | — | County |
| 29 Jan 2019 | Extreme Cold/Wind Chill | Cold | — | — | — | 1 | — | Forecast zone |
| 29 Jan 2019 | Extreme Cold/Wind Chill | Cold | — | — | — | 1 | — | Forecast zone |
| 13 Apr 2006 | Tornado | Tornado | F2 | $12M | — | — | 30 | County |
| 1 Jun 2008 | Flood | Flood | — | $230M | — | — | — | County |
| 15 May 1998 | Tornado | Tornado | F3 | $6.0M | — | — | 17 | County |
| 29 Jun 1998 | Thunderstorm Wind | Wind | — | $31M | $14M | — | 12 | County |
| 18 May 1997 | Hail | Hail | 2.75 in | $40M | — | — | — | County |
| 3 Feb 2008 | Winter Storm | Winter | — | — | — | — | 3 | Forecast zone |
| 28 Apr 1974 | Tornado | Tornado | F1 | $25K | — | — | 2 | County |
| 31 Mar 2023 | Tornado | Tornado | EF2 | — | — | — | 2 | County |
| 1 Aug 2003 | Drought | Drought | — | — | $15M | — | — | Forecast zone |
| 7 Jun 1994 | Hail | Hail | 1.50 in | $5K | $500K | — | 1 | County |
| 20 Aug 2010 | Lightning | Lightning | — | $1K | — | — | 1 | County |
| 11 Apr 2007 | Winter Weather | Winter | — | — | — | — | 1 | Forecast zone |
| 30 Jun 2014 | Thunderstorm Wind | Wind | 81 mph | — | — | — | 1 | County |
| 20 Oct 2015 | Lightning | Lightning | — | — | — | — | 1 | County |
| 1 Jul 2005 | Drought | Drought | — | — | $8.6M | — | — | Forecast zone |
Ranked by deaths, then injuries, then NCEI's damage estimate. Deaths and injuries are NCEI counts (direct plus indirect); no personal details are recorded here.
Federal disaster declarations
| Declared | Number | Type | Incident | Title | Programs |
|---|---|---|---|---|---|
| 17 Aug 2020 | DR-4557 | Major disaster | Severe Storm | Severe Storms | Public assistance |
| 23 Mar 2020 | DR-4483 | Major disaster | Biological | Covid-19 Pandemic | Individual assistance, Public assistance |
| 13 Mar 2020 | EM-3480 | Emergency | Biological | Covid-19 | Public assistance |
| 5 Aug 2014 | DR-4187 | Major disaster | Severe Storm | Severe Storms, Tornadoes, Straight-Line Winds, And Flooding | Public assistance |
| 2 Jul 2013 | DR-4126 | Major disaster | Severe Storm | Severe Storms, Tornadoes, And Flooding | Public assistance |
| 31 May 2013 | DR-4119 | Major disaster | Flood | Severe Storms, Straight-Line Winds, And Flooding | Public assistance |
| 27 May 2008 | DR-1763 | Major disaster | Severe Storm | Severe Storms, Tornadoes, And Flooding | Individual assistance, Public assistance |
| 4 Jan 2008 | DR-1737 | Major disaster | Severe Ice Storm | Severe Winter Storm | Public assistance |
| 14 Mar 2007 | DR-1688 | Major disaster | Severe Storm | Severe Winter Storms | Public assistance |
| 10 Sep 2005 | EM-3239 | Emergency | Hurricane | Hurricane Katrina Evacuation | Public assistance |
| 25 May 2004 | DR-1518 | Major disaster | Severe Storm | Severe Storms, Tornadoes, And Flooding | Individual assistance |
| 19 Jun 2002 | DR-1420 | Major disaster | Flood | Severe Storms And Flooding | Individual assistance |
| 2 Jul 1998 | DR-1230 | Major disaster | Flood | Severe Storms, Tornadoes And Flooding | Individual assistance, Public assistance |
| 24 Jun 1996 | DR-1121 | Major disaster | Severe Storm | Severe Storms And Flooding | Public assistance |
| 9 Jul 1993 | DR-996 | Major disaster | Flood | Severe Storms & Flooding | Individual assistance, Public assistance |
| 12 Jul 1991 | DR-911 | Major disaster | Flood | Severe Storms & Flooding | Individual assistance |
| 6 Sep 1990 | DR-879 | Major disaster | Flood | Severe Storms & Flooding | Individual assistance |
| 26 May 1990 | DR-868 | Major disaster | Flood | Severe Storms & Flooding | Individual assistance, Public assistance |
| 24 Jun 1974 | DR-443 | Major disaster | Flood | Severe Storms & Flooding | Individual assistance, Public assistance |
| 23 May 1973 | DR-386 | Major disaster | Flood | Severe Storms & Flooding | Individual assistance, Public assistance |
| 18 Aug 1972 | DR-348 | Major disaster | Flood | Severe Storms & Flooding | Public assistance |
| 14 Aug 1969 | DR-269 | Major disaster | Flood | Heavy Rains & Flooding | Individual assistance, Public assistance |
| 29 May 1968 | DR-240 | Major disaster | Tornado | Tornadoes & Severe Storms | Individual assistance, Public assistance |
| 22 Apr 1965 | DR-193 | Major disaster | Flood | Flooding | Individual assistance, Public assistance |
Declarations in which FEMA designated this county, from the OpenFEMA Disaster Declarations Summaries (v2). DR: major disaster; EM: emergency; FM: fire management assistance. Programs show whether individual or public assistance was made available.
Flood insurance claims
| Year of loss | Claims | Paid claims | Amount paid | Average paid |
|---|---|---|---|---|
| 2025 | 1 | 0 | $0 | — |
| 2018 | 3 | 3 | $118,633 | $39,544 |
| 2016 | 4 | 4 | $109,871 | $27,468 |
| 2015 | 1 | 1 | $4,592 | $4,592 |
| 2014 | 24 | 21 | $56,163 | $2,674 |
| 2013 | 54 | 44 | $247,760 | $5,631 |
| 2012 | 5 | 3 | $5,173 | $1,724 |
| 2010 | 6 | 2 | $63,581 | $31,791 |
| 2009 | 7 | 5 | $13,822 | $2,764 |
| 2008 | 181 | 168 | $27,418,678 | $163,206 |
| 2007 | 4 | 3 | $57,708 | $19,236 |
| 2006 | 1 | 0 | $0 | — |
| 2002 | 3 | 3 | $20,122 | $6,707 |
| 1998 | 2 | 2 | $11,494 | $5,747 |
| 1996 | 9 | 3 | $13,195 | $4,398 |
| 1994 | 2 | 0 | $0 | — |
| 1993 | 112 | 89 | $3,632,883 | $40,819 |
| 1991 | 9 | 8 | $39,446 | $4,931 |
| 1990 | 6 | 5 | $82,790 | $16,558 |
| 1986 | 1 | 0 | $0 | — |
| 1983 | 1 | 0 | $0 | — |
| 1982 | 2 | 2 | $4,359 | $2,180 |
| 1981 | 2 | 1 | $391 | $391 |
| 1980 | 2 | 1 | $1,975 | $1,975 |
| 1978 | 4 | 3 | $33,129 | $11,043 |
OpenFEMA NFIP claims (v3, as of 8 Sep 2026), aggregated by year of loss; amounts are building, contents and increased-cost-of-compliance payments as recorded. Repetitive-loss counts from the NFIP Multiple Loss Properties file (2 Aug 2026); policies in force from the NFIP Residential Penetration Rates file (3 Aug 2026).
National Risk Index
| Hazard (NRI) | Risk rating | Expected annual loss |
|---|---|---|
| Tornado | $36,235,301 | |
| Inland flooding | $27,464,976 | |
| Strong wind | $10,494,805 | |
| Cold wave | $10,482,489 | |
| Hail | $4,359,207 | |
| Heat wave | $3,518,204 | |
| Drought | $1,462,135 | |
| Lightning | $830,338 | |
| Winter weather | $491,672 | |
| Ice storm | $428,273 | |
| Earthquake | $294,022 | |
| Wildfire | $163,721 | |
| Landslide | $20,458 | |
| Hurricane | $4,595 |
FEMA National Risk Index, December 2025 release. Ratings are FEMA's relative comparison of counties; expected annual loss is FEMA's modelled estimate of average yearly building, population and agriculture loss. See how to read the NRI.
Hurricane and tropical storm passes
| Storm | Year | Closest approach | Max wind while within 100 mi |
|---|---|---|---|
| Unnamed Atlantic storm | 1900 | 43 mi | 46 mph |
HURDAT2 best-track positions at tropical-storm strength (34 kt) or more, measured from the county's Census centre point; through the 2025 season. Distance from a track is not the same as the extent of the storm's wind, rain or surge.
ZIP codes with flood claims
ZIP codes whose NFIP claims carry this county's code, with the number of claims. Five or more claims are needed for a ZIP page to be indexed.
Questions and answers
How often does it hail in Johnson County, IA?
NCEI records 229 hail events in Johnson County since 1950, in 40 different years; that is about 3.0 recorded events a year. 48 reports were golf-ball size (1.75 in) or larger.
Has Johnson County had a tornado?
Yes. NCEI records 46 tornadoes in Johnson County since 1950, 12 of them rated (E)F2 or stronger. Tornado deaths recorded: 1.
When was the last federal disaster declaration for Johnson County?
17 Aug 2020: Severe Storms, a major disaster declaration for severe storm. The county appears in 24 declarations since 1953.
How many flood insurance claims have been filed in Johnson County, and how much was paid?
446 NFIP claims since 1978, 371 of them paid, for $32M in total. FEMA publishes these figures redacted and aggregated; individual properties are not identified.
Is Johnson County in the National Risk Index's high-risk band?
FEMA's National Risk Index (December 2025) rates the county "Relatively Moderate" for overall risk, "Relatively Moderate" for expected annual loss, "Very Low" for social vulnerability and "Very High" for community resilience. These ratings are FEMA's relative comparison across all US counties.
How does Johnson County compare with the rest of Iowa?
147.0 recorded events per 100 square miles against 124.6 statewide, and 2.9 NFIP claims per 1,000 residents against 4.6. The comparison table on this page shows each measure beside the state and national figures.
Provenance
Storm events: NOAA NCEI Storm Events Database, yearly details files through 30 Jun 2026 (public domain). Declarations: OpenFEMA DisasterDeclarationsSummaries v2, refreshed 1 Oct 2026. Flood claims: OpenFEMA NfipClaims v3 as of 8 Sep 2026; NfipMultipleLossProperties v1 (2 Aug 2026); NfipResidentialPenetrationRates v1 (3 Aug 2026). Risk index: FEMA National Risk Index, December 2025. Hurricane tracks: NHC HURDAT2 through 2025. Population and area: US Census Bureau, 2021 vintage. Built 1 Oct 2026; see the methodology and corrections pages. Hazard hubs: Hail · Tornado · Flood · Wind · Winter.