Enter any address in McHenry County, Illinois to see its FEMA flood zone
Flash flooding from summer thunderstorms is a significant hazard in McHenry County. Between 1994 and 2024, NOAA Storm Events data recorded 26 flood events and 17 flash flood events. For example, on June 22, 2024, torrential rainfall in northeast Illinois led to widespread flash flooding, with some areas receiving 3-6 inches of rain. Earlier, on May 7, 2024, scattered thunderstorms caused localized flooding across parts of northern Illinois.
National Flood Insurance Program (NFIP) data indicates that properties in Zone A have experienced the most claims, with an average payout of $8,784 and an average water depth of 2.1 feet. Properties in Zone X_UNSHADED have also seen substantial claims, with an average payout of $8,391 and an average water depth of 7.1 feet, suggesting a higher potential for deeper flooding. Homeowners in Zone A and Zone X_UNSHADED, as well as those in areas with a history of flash flooding, should pay close attention to flood risk.
Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.
3 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.
McHenry County, Illinois has recorded 43 flood-related events since 1996 according to NOAA's Storm Events Database, including 17 flash floods and 26 river or area floods. The county has received 16 federal disaster declarations, 5 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 |
|---|---|---|
| Covid-19 | Biological | Jan 20, 2020 |
| Covid-19 Pandemic | Biological | Jan 20, 2020 |
| Severe Storms, Straight-line Winds, And Flooding | Flood | Apr 16, 2013 |
| Severe Winter Storm And Snowstorm | Snowstorm | Jan 31, 2011 |
| Record Snow And Near Record Snow | Snowstorm | Feb 5, 2008 |
| Snow | Snowstorm | Nov 30, 2006 |
| Hurricane Katrina Evacuation | Hurricane | Aug 29, 2005 |
| Illinois Winter Snow Storms | Snowstorm | Dec 11, 2000 |
| Winter Storm 1/1/99 | Snowstorm | Jan 1, 1999 |
| Severe Storms & Flooding | Flood | Apr 13, 1993 |
NOAA Storm Events Database (1996–2025)
Source: NOAA National Weather Service Storm Events Database.
| Type | Date | Damage |
|---|---|---|
| Flash Flood | Jun 22, 2024 | 0.00K |
| Flood | May 7, 2024 | 0.00K |
| Flash Flood | Jul 5, 2022 | 0.00K |
| Flood | Jul 5, 2022 | 0.00K |
| Flash Flood | Aug 24, 2021 | 0.00K |
| Flood | Jun 29, 2020 | 0.00K |
| Flood | May 23, 2020 | 0.00K |
| Flash Flood | May 14, 2020 | 0.00K |
| Flash Flood | Sep 13, 2019 | 0.00K |
| Flash Flood | Sep 12, 2019 | 0.00K |
Flash Flood — Jun 22, 2024
A line of severe thunderstorms dropped south across northern Illinois during the evening and night of the 22nd. The line produced four EF-0 tornadoes in addition to widespread wind damage across the Chicago metro. Many also saw torrential rainfall and localized flash flooding, particularly in extreme northeast Illinois north of the I-90 corridor where a widespread 3-6 of rain fell.
Flood — May 7, 2024
Scattered thunderstorms moved across parts of northern Illinois during the afternoon of May 7th producing large hail, localized flooding and one tornado. Additional scattered thunderstorms developed during the evening of May 7th producing locally severe winds.
Flash Flood — Jul 5, 2022
Scattered thunderstorms moved across parts of northern Illinois during the evening of July 5th into the early morning of July 6th producing scattered wind damage and flooding.
Flood — Jul 5, 2022
Scattered thunderstorms moved across parts of northern Illinois during the evening of July 5th into the early morning of July 6th producing scattered wind damage and flooding.
Flash Flood — Aug 24, 2021
Scattered thunderstorms moved across portions of northern Illinois during the afternoon and evening of August 24th.
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 McHenry County, Illinois:
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 McHenry County, Illinois 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.