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Flood in Johnson County, Iowa
75 floods and flash floods events in the NCEI Storm Events record, 1950 to 2026. Event types counted: Flood, Flash Flood, Coastal Flood, Lakeshore Flood.
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. Storm records through 30 Jun 2026.
NCEI records 75 flood events in Johnson County, Iowa, between 1950 and 2026, spread over 23 years.
June is the busiest month, with 32 of the recorded events. The last 20 years account for 56 events against 19 in the 20 years before, a change that reflects reporting practice as much as weather.
The county holds 1% of the 7,383 flood events recorded in Iowa; its 12.2 per 100 square miles compares with 13.2 statewide.
Compared with Iowa
| Measure | Johnson County | Iowa | US |
|---|---|---|---|
| Flood events since 1950 | 75 | 7,383 | 183,559 |
| Per 100 square miles | 12.2 | 13.2 | 5.2 |
| Per 10,000 residents | 4.8 | 23.1 | 5.5 |
| Deaths recorded | 0 | 18 | 2,961 |
| Busiest month | June | June | June |
By year
Seasonality
0Feb
2Mar
0Apr
3May
6Jun
32Jul
21Aug
8Sep
0Oct
3Nov
0Dec
0
Recorded events
All 75 events, most recent first. Magnitude is hail size, tornado rating or wind speed as recorded.
| Date | Event type | Magnitude | Property damage | Crop damage | Deaths | Injuries | Geography |
|---|---|---|---|---|---|---|---|
| 17 Jun 2026 | Flash Flood | — | — | — | — | — | County |
| 10 Jul 2024 | Flash Flood | — | — | — | — | — | County |
| 10 Jul 2024 | Flash Flood | — | — | — | — | — | County |
| 2 Jul 2024 | Flash Flood | — | — | — | — | — | County |
| 2 Jul 2024 | Flash Flood | — | — | — | — | — | County |
| 2 Jul 2024 | Flash Flood | — | — | — | — | — | County |
| 8 Jul 2022 | Flash Flood | — | — | — | — | — | County |
| 25 Jun 2022 | Flash Flood | — | — | — | — | — | County |
| 27 Jun 2020 | Flash Flood | — | — | — | — | — | County |
| 9 Jun 2020 | Flash Flood | — | — | — | — | — | County |
| 29 May 2019 | Flash Flood | — | — | — | — | — | County |
| 28 May 2019 | Flash Flood | — | — | — | — | — | County |
| 16 May 2019 | Flash Flood | — | — | — | — | — | County |
| 7 Oct 2018 | Flood | — | — | — | — | — | County |
| 5 Oct 2018 | Flash Flood | — | — | — | — | — | County |
| 21 Jul 2017 | Flash Flood | — | — | — | — | — | County |
| 21 Jul 2017 | Flash Flood | — | — | — | — | — | County |
| 12 Aug 2016 | Flash Flood | — | — | — | — | — | County |
| 11 Aug 2016 | Flash Flood | — | — | — | — | — | County |
| 11 Aug 2016 | Flash Flood | — | $1.5M | — | — | — | County |
| 22 Jun 2016 | Flash Flood | — | — | — | — | — | County |
| 1 Jul 2014 | Flood | — | — | — | — | — | County |
| 30 Jun 2014 | Flash Flood | — | — | — | — | — | County |
| 30 Jun 2014 | Flash Flood | — | — | — | — | — | County |
| 23 Jun 2014 | Flood | — | — | — | — | — | County |
| 24 Jun 2013 | Flash Flood | — | — | — | — | — | County |
| 18 Apr 2013 | Flood | — | — | — | — | — | County |
| 17 Apr 2013 | Flash Flood | — | $250K | — | — | — | County |
| 4 Aug 2010 | Flood | — | $75K | — | — | — | County |
| 4 Aug 2010 | Flash Flood | — | — | — | — | — | County |
| 30 Jul 2010 | Flash Flood | — | $25K | — | — | — | County |
| 15 Jun 2010 | Flood | — | $375K | — | — | — | County |
| 15 Jun 2010 | Flash Flood | — | $250K | — | — | — | County |
| 27 Aug 2009 | Flash Flood | — | $100K | — | — | — | County |
| 11 Jul 2009 | Flood | — | — | — | — | — | County |
| 23 Jun 2009 | Flash Flood | — | — | — | — | — | County |
| 22 Jun 2009 | Flood | — | $250K | — | — | — | County |
| 21 Jun 2009 | Flash Flood | — | $100K | — | — | — | County |
| 2 Jul 2008 | Flash Flood | — | — | — | — | — | County |
| 12 Jun 2008 | Flash Flood | — | $500K | — | — | — | County |
| 8 Jun 2008 | Flash Flood | — | $25K | — | — | — | County |
| 3 Jun 2008 | Flash Flood | — | — | — | — | — | County |
| 1 Jun 2008 | Flood | — | $230M | — | — | — | County |
| 1 Apr 2008 | Flood | — | — | — | — | — | County |
| 8 Aug 2007 | Flash Flood | — | — | — | — | — | County |
| 17 Jul 2007 | Flash Flood | — | — | — | — | — | County |
| 16 Jul 2007 | Flash Flood | — | — | — | — | — | County |
| 16 Jul 2007 | Flash Flood | — | — | — | — | — | County |
| 22 Jun 2007 | Flash Flood | — | — | — | — | — | County |
| 22 Jun 2007 | Flash Flood | — | — | — | — | — | County |
| 22 Jun 2007 | Flash Flood | — | — | — | — | — | County |
| 22 Jun 2007 | Flash Flood | — | — | — | — | — | County |
| 22 Jun 2007 | Flash Flood | — | — | — | — | — | County |
| 22 Jun 2007 | Flash Flood | — | — | — | — | — | County |
| 22 Jun 2007 | Flash Flood | — | $500K | — | — | — | County |
| 22 Jun 2007 | Flash Flood | — | — | — | — | — | County |
| 11 Jun 2004 | Flood | — | — | — | — | — | Forecast zone |
| 1 Jun 2004 | Flood | — | — | — | — | — | Forecast zone |
| 9 May 2003 | Flood | — | $500K | — | — | — | Forecast zone |
| 23 Aug 2002 | Flash Flood | — | — | — | — | — | County |
| 11 Jul 2002 | Flood | — | — | — | — | — | County |
| 11 Jul 2002 | Flood | — | — | — | — | — | County |
| 24 Feb 2001 | Flood | — | — | — | — | — | County |
| 10 Jul 2000 | Flood | — | — | — | — | — | County |
| 4 Jul 2000 | Flood | — | — | — | — | — | County |
| 1 Jul 2000 | Flood | — | — | — | — | — | Forecast zone |
| 13 Jun 2000 | Flash Flood | — | — | — | — | — | County |
| 1 Jun 2000 | Flood | — | — | — | — | — | Forecast zone |
| 23 Jul 1999 | Flood | — | — | — | — | — | Forecast zone |
| 12 Jun 1999 | Flood | — | — | — | — | — | County |
| 10 Jun 1999 | Flood | — | — | — | — | — | County |
| 17 May 1999 | Flood | — | — | — | — | — | Forecast zone |
| 17 Oct 1998 | Flash Flood | — | — | — | — | — | County |
| 20 Feb 1997 | Flash Flood | — | — | — | — | — | County |
| 9 May 1996 | Flood | — | — | — | — | — | Forecast zone |
Questions and answers
How many flood events has Johnson County had?
75 events in the NCEI Storm Events record between 1950 and 2026. Reporting of floods and flash floods became far more complete after 1996, so early decades undercount.
When was the last recorded flood event in Johnson County?
17 Jun 2026 (Flash Flood). Records reach NCEI about 120 days after the month ends.
What was the most damaging flood event recorded in Johnson County?
The flood of 1 Jun 2008, with property damage estimated by NCEI at $230M.
How does Johnson County compare with Iowa for flood?
12.2 events per 100 square miles against 13.2 statewide; the county holds 75 of the state's 7,383 recorded events.
Provenance
NOAA NCEI Storm Events Database, yearly details files through 30 Jun 2026, public domain. County-recorded events plus zone-recorded events whose forecast zone is named for the county (marked "Forecast zone"). Population and area from the US Census Bureau (2021). Built 1 Oct 2026. See the methodology, the Flood hub and the county page.