Enter any address in LaSalle County, Illinois to see its FEMA flood zone
Flash flooding from thunderstorms is the dominant flood character in LaSalle County. Between 2005 and 2025, NOAA Storm Events data recorded 36 flash flood events and 45 flood events. For example, on August 17, 2025, a strong thunderstorm brought torrential rainfall to parts of the county. Another event on August 18, 2025, saw rounds of thunderstorms cause flash flooding across northern Illinois, with initial reports estimating $8.8 million in damages.
National Flood Insurance Program (NFIP) claims data shows a significant number of payouts for properties in Zone A, with an average payout of $20,374 and an average water depth of 9.4 feet. Properties in Zone X also experienced substantial claims, averaging $19,997 with an average water depth of 8.1 feet. Homeowners in Zone A and Zone X, as well as those in Zone X_UNSHADED with an average water depth of 12.1 feet, should pay the most attention to flood risk.
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.
LaSalle County, Illinois has recorded 81 flood-related events since 1996 according to NOAA's Storm Events Database, including 36 flash floods and 45 river or area floods. The county has received 20 federal disaster declarations, 6 of which involved flooding or coastal storms. Enter any address above to check its FEMA flood zone designation.
FEMA Disaster Declarations (1967–2020)
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 Tornadoes | Tornado | Nov 17, 2013 |
| 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 Tornadoes | Severe Storm | Apr 20, 2004 |
NOAA Storm Events Database (1996–2025)
Source: NOAA National Weather Service Storm Events Database.
| Type | Date | Damage |
|---|---|---|
| Flood | Jan 31, 2025 | 0.00K |
| Flash Flood | Aug 18, 2025 | 0.00K |
| Flash Flood | Aug 17, 2025 | 0.00K |
| Flood | Apr 28, 2024 | 0.00K |
| Flood | Jan 27, 2024 | 0.00K |
| Flood | Jan 16, 2024 | 0.00K |
| Flood | Jul 10, 2024 | 0.00K |
| Flood | May 7, 2023 | 0.00K |
| Flood | Feb 22, 2022 | 0.00K |
| Flood | Feb 18, 2022 | 0.00K |
Flood — Jan 31, 2025
Persistent moderate to heavy rain during the morning of the 31st resulted in a few instances of localized flooding, mainly around the interior Chicago metro area. Despite rain reports largely below 1.5, NWS Chicago recorded a 12 frost depth in Romeoville on the morning of the 31st, which made the area more susceptible to flooding.
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.
Flash Flood — Aug 17, 2025
During the evening of the 17th, a strong thunderstorm brought torrential rainfall to parts of LaSalle County.
Flood — Apr 28, 2024
Several hours of moderate to heavy rainfall during the night of the 27th into the morning of the 28th resulted in numerous instances flooding across the Rutland area in LaSalle County.
Flood — Jan 27, 2024
Warming temperatures, melting snow and melting ice along with periods of heavy rain, caused river rises, localized flooding along rivers and flash flooding due to an ice jam near Wilmington.
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 LaSalle 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 LaSalle 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.