987 flood insurance claims·$7.6M paid·5 federal flood & hurricane disasters
Share of the whole county outline, rivers and lakes included; parts FEMA hasn’t mapped count as zero.
Shaded areas are FEMA’s mapped flood hazard zones in and around McHenry County, Illinois. Zoomed out they are simplified; at street level the map switches to FEMA’s exact layer. Tap anywhere to check that spot, or search an address above.
Flooding driven by general floods and flash floods from severe thunderstorms dominates McHenry County, based on 26 flood events and 17 flash flood events recorded over the last 30 years in the NOAA Storm Events Database. Recent occurrences include heavy rainfall and localized flash flooding from severe thunderstorms in June 2024, as well as scattered thunderstorms producing localized flooding in May 2024 and July 2022.
National Flood Insurance Program records show claims across multiple zones, indicating that flood risk extends beyond high-risk areas. Zone A accounts for the highest claim volume with 687 claims averaging a $12,277 payout and an average recorded water depth of 6 inches. Properties designated as Zone UNKNOWN recorded 140 claims with an average payout of $2,392 and an average water depth of 2 inches. Moderate-to-low risk zones also experienced impacts, including 75 claims in Zone X with an average payout of $9,150 and an average water depth of 7 inches, 54 claims in unshaded Zone X with an average payout of $10,554 and an average water depth of 13 inches, and 31 claims in shaded Zone X with an average payout of $7,283 and an average water depth of 2 inches.
Homeowners and real estate professionals in Zone A and unshaded Zone X should pay the closest attention to flood risk, as these areas experienced the highest claim counts and highest average water depths.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
11% of McHenry County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
772 NFIP claims with a recorded rated flood zone, 1978 to date. The zone is the one FEMA used to rate that policy, which may not match today’s map. Source: OpenFEMA NFIP claims.
In flood insurance claims here that reported a flood depth, the average was 6 inches.
Drawn to scale against an 80-inch door. Even a few inches soaks flooring, the bottom of the drywall and anything plugged in near the floor.
Average of the depths reported on claims (zero and implausible values left out); FEMA’s record doesn’t say exactly where each depth was measured. Source: OpenFEMA NFIP claims.
The worst year was 2013, with 165 claims and $2.4M paid, the year of Severe Storms, Straight-line Winds, and Flooding.
Bar height is scaled by square root so ordinary years stay visible next to the worst one. NFIP claims by year of loss. Source: OpenFEMA.
3 NOAA storm reports from McHenry County describe what happened, in the words of the forecasters who covered it. Read the Illinois flood stories →
16 federal disaster declarations since 1965, 5 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Storms, Straight-line Winds, And Flooding | Apr 16, 2013 |
| Severe Winter Storm And Snowstorm | Jan 31, 2011 |
| Record Snow And Near Record Snow | Feb 5, 2008 |
| Snow | Nov 30, 2006 |
| Hurricane Katrina Evacuation | Aug 29, 2005 |
| Illinois Winter Snow Storms | Dec 11, 2000 |
| Winter Storm 1/1/99 | Jan 1, 1999 |
| Severe Storms & Flooding | Apr 13, 1993 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
43 since 1996: 17 flash floods and 26 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Jun 22, 2024 | — |
| Flood | May 7, 2024 | — |
| Flash Flood | Jul 5, 2022 | — |
| Flood | Jul 5, 2022 | — |
| Flash Flood | Aug 24, 2021 | — |
| Flood | Jun 29, 2020 | — |
| Flood | May 23, 2020 | — |
| Flash Flood | May 14, 2020 | — |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
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.
National Weather Service narratives, lightly trimmed. Source: NOAA Storm Events Database.
Every colour on the map above is a place on this drawing: where the ground sits relative to the flood FEMA plans for.
If a building in McHenry County is in a high-risk zone (A or V) and its mortgage comes from a federally regulated or insured lender, or is federally backed, flood insurance is required.
Outside those zones it is optional, and often worth having: from 2014 to 2024 nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area. Since Risk Rating 2.0, NFIP premiums are set for each building, so the only reliable price is a quote: FloodSmart.gov or a local agent.