Enter any address in Johnson County, Iowa to see its FEMA flood zone
Flash flooding from summer thunderstorms is the dominant flood character in Johnson County, Iowa. Over the past 30 years, NOAA Storm Events data shows 49 recorded flash flood events compared to 25 general flood events. Recent examples include flash flooding near Iowa City in July 2024, associated with severe winds and rainfall of 2 to 3.50 inches, and another instance on July 10, 2024, where heavy rain from thunderstorms led to flash flooding in the Iowa City metropolitan area.
National Flood Insurance Program (NFIP) claims data indicates that properties in Zone A have experienced the most claims, with an average payout of $72,860 and an average water depth of 8.1 feet. While Zone X and Zone X_SHADED also show claims, properties in Zone X_UNSHADED have had fewer claims with significantly lower average water depths. Homeowners in Zone A, and those located near waterways, should pay the most attention to flood risk.
Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.
23 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.
Johnson County, Iowa has recorded 74 flood-related events since 1996 according to NOAA's Storm Events Database, including 49 flash floods and 25 river or area floods. The county has received 24 federal disaster declarations, 12 of which involved flooding or coastal storms. Enter any address above to check its FEMA flood zone designation.
FEMA Disaster Declarations (1965–2020)
Source: OpenFEMA Disaster Declarations Summaries.
| Declaration | Type | Date |
|---|---|---|
| Severe Storms | Severe Storm | Aug 10, 2020 |
| Covid-19 | Biological | Jan 20, 2020 |
| Covid-19 Pandemic | Biological | Jan 20, 2020 |
| Severe Storms, Tornadoes, Straight-line Winds, And Flooding | Severe Storm | Jun 26, 2014 |
| Severe Storms, Tornadoes, And Flooding | Severe Storm | May 19, 2013 |
| Severe Storms, Straight-line Winds, And Flooding | Flood | Apr 17, 2013 |
| Severe Storms, Tornadoes, And Flooding | Severe Storm | May 25, 2008 |
| Severe Winter Storm | Severe Ice Storm | Dec 10, 2007 |
| Severe Winter Storms | Severe Storm | Feb 23, 2007 |
| Hurricane Katrina Evacuation | Hurricane | Aug 29, 2005 |
NOAA Storm Events Database (1996–2025)
Source: NOAA National Weather Service Storm Events Database.
| Type | Date | Damage |
|---|---|---|
| Flash Flood | Jul 10, 2024 | 0.00K |
| Flash Flood | Jul 2, 2024 | 0.00K |
| Flash Flood | Jun 25, 2022 | 0.00K |
| Flash Flood | Jul 8, 2022 | 0.00K |
| Flash Flood | Jun 27, 2020 | 0.00K |
| Flash Flood | Jun 9, 2020 | 0.00K |
| Flash Flood | May 29, 2019 | 0.00K |
| Flash Flood | May 28, 2019 | 0.00K |
| Flash Flood | May 16, 2019 | 0.00K |
| Flood | Oct 7, 2018 | 0.00K |
Flash Flood — Jul 10, 2024
Thunderstorms developed in central Iowa and moved across eastern Iowa during the late afternoon and evening hours of July 10th. These storms produced damaging winds and heavy rainfall across the area. Heavy rain led to flash flooding as the storms moved into the Iowa City metropolitan area.
Flash Flood — Jul 2, 2024
A line of organized storms surged into eastern Iowa late in the day and produced severe winds and heavy rainfall. The strongest storms occurred in a swath just south of Interstate 80, including near Iowa City, producing thunderstorm wind gusts of 60 to 80 MPH. There were rainfall amounts of 2 to 3.50 inches.
Flash Flood — Jun 25, 2022
Several intense clusters of storms moved through eastern Iowa into Illinois. The morning cluster produced flash flooding. In the afternoon and evening, a cluster of intense thunderstorms moved through far eastern Iowa into west central and northwest Illinois the evening of June 25th, with torrential rainfall and wind damage along it's way.
Flash Flood — Jul 8, 2022
Rain showers produced heavy rain of 3 to 5 inches across the warned area. This led to flash flooding in Johnson county and Muscatine County.
Flash Flood — Jun 27, 2020
A disturbance moving across the eastern Iowa on the 27th produced slow moving showers and thunderstorms across the area. This led to flash flooding in northwest Johnson County.
Source: NOAA National Weather Service Storm Events Database.
Source: OpenFEMA NFIP Individual Claims (2.25M records analyzed).
FEMA assigns flood zone designations to areas in Johnson County, Iowa:
AE High Risk — 1% annual chance of flooding. Insurance required.
VE Very High Risk — Coastal flooding with wave action.
X (Shaded) Moderate Risk — 500-year floodplain.
X Low Risk — Outside major floodplains.
Properties in Johnson County, Iowa that are in FEMA-designated Special Flood Hazard Areas (zones A and V) with federally backed mortgages are required to carry flood insurance.
Even outside high-risk zones, flood insurance is recommended. From 2014 to 2024, nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area.
Visit FloodSmart.gov to find an agent and get a quote.