Enter any address in Knox County, Illinois to see its FEMA flood zone
Flash flooding from thunderstorms is the dominant flood character in Knox County, IL. Between 2013 and 2023, NOAA Storm Events data recorded 34 flash flood events and 11 flood events. For example, on July 8, 2022, scattered thunderstorms produced isolated flash flooding. Similarly, on June 6, 2022, localized flash flooding occurred due to 1 to 3 inches of rainfall in a short period.
National Flood Insurance Program (NFIP) claims data indicates that properties in Zone A experienced an average payout of $13,343 with an average water depth of 11.8 feet. Properties in Zone X also saw significant payouts, averaging $10,755 with an average water depth of 0.8 feet. Homeowners in Zone A, Zone X, and those without a Base Flood Elevation (BFE) should pay the most attention to flood risk.
Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.
13 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.
Knox County, Illinois has recorded 45 flood-related events since 1996 according to NOAA's Storm Events Database, including 34 flash floods and 11 river or area floods. The county has received 11 federal disaster declarations, 4 of which involved flooding or coastal storms. Enter any address above to check its FEMA flood zone designation.
FEMA Disaster Declarations (1974–2020)
Source: OpenFEMA Disaster Declarations Summaries.
| Declaration | Type | Date |
|---|---|---|
| Covid-19 | Biological | Jan 20, 2020 |
| Covid-19 Pandemic | Biological | Jan 20, 2020 |
| Severe Storms And Flooding | Flood | Feb 24, 2019 |
| 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 | Aug 20, 2007 |
| Snow | Snowstorm | Nov 30, 2006 |
| Hurricane Katrina Evacuation | Hurricane | Aug 29, 2005 |
| 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 | Jul 8, 2022 | 0.00K |
| Flash Flood | Jun 6, 2022 | 0.00K |
| Flash Flood | May 28, 2019 | 0.00K |
| Flash Flood | Sep 7, 2018 | 0.00K |
| Flash Flood | Oct 14, 2017 | 0.00K |
| Flash Flood | Jul 16, 2015 | 0.00K |
| Flash Flood | Jun 14, 2015 | 0.00K |
| Flash Flood | Jul 11, 2015 | 0.00K |
| Flash Flood | Jun 10, 2015 | 0.00K |
| Flash Flood | Jun 7, 2015 | 0.00K |
Flash Flood — Jul 8, 2022
A weak low pressure system was located in southwestern Illinois on the afternoon of July 8, 2022, with a stationary front draped near the I-70 corridor. A secondary cold front pushed into central Illinois from the north, and scattered thunderstorms developed along both boundaries. As storm clusters progressed to the southeast, they produced isolated flash flooding, hail, and wind damage.
Flash Flood — Jun 6, 2022
A slow-moving cold front interacted with a warm and moist environment to trigger clusters of thunderstorms across north-central Illinois during the late afternoon and evening of June 6th. Some of the storms produced rainfall of 1 to 3 inches in a short period of time, leading to localized flash flooding. The flooding was primarily focused along and north of an Abingdon to Lacon line.
Flash Flood — May 28, 2019
An upper-level disturbance tracking along a nearly stationary frontal boundary triggered a line of strong to severe thunderstorms across west-central Illinois during the late evening of May 28th. The storms tracked eastward and gradually weakened as they approached the I-55 corridor by the early morning of May 29th. Wind gusts of 60-70 mph downed numerous tree branches and power lines as the ...
Flash Flood — Sep 7, 2018
Heavy rain impacted central and southeast Illinois as the remnants of Tropical Storm Gordon tracked from Arkansas during the afternoon of September 7th to southern Ohio by the afternoon of September 9th. The rainfall was further enhanced by a weak cold front dropping southward out of the Upper Midwest. Rainfall was heaviest south of I-70 in closer proximity to the track of the storm, with amo...
Flash Flood — Oct 14, 2017
A slow-moving cold front interacting with an unseasonably warm and humid airmass triggered several rounds of thunderstorms across west-central Illinois during the afternoon and evening of October 14th. The strongest and most persistent storms impacted Knox County, producing scattered wind damage and dropping locally heavy rainfall of 2 to 3 inches. Numerous streets in the city of Galesburg we...
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 Knox 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 Knox 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.