Enter any address in DeKalb County, Illinois to see its FEMA flood zone
Flash flooding from thunderstorms is the dominant flood character in DeKalb County. Over the past 30 years, NOAA Storm Events data shows 27 flash flood events and 19 flood events. For example, torrential rainfall caused flash flooding across northern Illinois on August 18, 2025, contributing to an estimated $8.8 million in flood damages across the region. Isolated flooding also occurred on July 14, 2024, alongside heavy rain and wind gusts.
National Flood Insurance Program (NFIP) claims data indicates that properties in Zone A have experienced the most claims, with an average payout of $13,418 and an average water depth of 4.5 feet. Properties in Zone X, though fewer in number, have seen significantly higher average payouts ($20,181) and water depths (9.2 feet). Homeowners in Zone A and Zone X, as well as those in areas with unknown flood risk, should pay particular attention to flood potential.
Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.
12 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.
DeKalb County, Illinois has recorded 46 flood-related events since 1996 according to NOAA's Storm Events Database, including 27 flash floods and 19 river or area floods. The county has received 12 federal disaster declarations, 3 of which involved flooding or coastal storms. Enter any address above to check its FEMA flood zone designation.
FEMA Disaster Declarations (1973–2020)
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 |
| Severe Storms And Flooding | Severe Storm | Sep 13, 2008 |
| Severe Storms And Flooding | Severe Storm | Aug 20, 2007 |
| Snow | Snowstorm | Nov 30, 2006 |
| Hurricane Katrina Evacuation | Hurricane | Aug 29, 2005 |
| Severe Storms And Flooding | Severe Storm | Jul 17, 1996 |
| Blizzards & Snowstorms | Snowstorm | Jan 16, 1979 |
NOAA Storm Events Database (1996–2025)
Source: NOAA National Weather Service Storm Events Database.
| Type | Date | Damage |
|---|---|---|
| Flash Flood | Aug 18, 2025 | 0.00K |
| Flood | Jul 14, 2024 | 0.00K |
| Flood | Aug 28, 2022 | 0.00K |
| Flash Flood | Aug 8, 2022 | 0.00K |
| Flood | Jul 6, 2022 | 0.00K |
| Flash Flood | May 23, 2020 | 0.00K |
| Flash Flood | May 14, 2020 | 0.00K |
| Flood | Jul 19, 2017 | 0.00K |
| Flood | Oct 14, 2017 | 0.00K |
| Flash Flood | Apr 18, 2013 | 0.00K |
Flash Flood — Aug 18, 2025
During the afternoon and evening of the 18th, a few rounds of thunderstorms brought torrential rainfall to much of northern Illinois resulting in flash flooding. One particularly strong storm also produced damaging winds in DeKalb County. Initial reports estimate $8.8 million in flood damages around northern and northeast Illinois, and around $2.5 million in the city of Chicago alone.
Flood — Jul 14, 2024
Scattered thunderstorms moved across northern Illinois during the morning of July 14th producing isolated wind damage, heavy rain and isolated flooding. Numerous locations reported thunderstorm wind gusts between 40 and 50 mph.
Flood — Aug 28, 2022
Scattered thunderstorms moved across northern Illinois during the afternoon and early evening of August 28th producing scattered wind damage.
Flash Flood — Aug 8, 2022
Heavy rain caused flash flooding across parts of northwest Illinois during the morning of August 8th when rainfall of 3 to 5 inches with locally higher amounts fell. Previous rainfall the day before brought two day rainfall totals to 6 to 9 inches across many areas across northwest Illinois. A church was struck by lightning in Rockford during the morning of August 8th causing significant dama...
Flood — Jul 6, 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.
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 DeKalb 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 DeKalb 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.