Enter any address in Jefferson County, Illinois to see its FEMA flood zone
Flash flooding from intense rainfall events is a primary flood concern in Jefferson County, IL. Over the past 30 years, the NOAA Storm Events Database has recorded 34 flash flood events and 15 flood events, with the latter resulting in 3 fatalities. Recent examples include significant rainfall in July 2024, which caused extensive street flooding in Mount Vernon and rising creek levels across the county, impacting areas north of Tamaroa. Another event in August 2024 saw a squall line produce wind damage and power outages across Southern Illinois, with heavy rain contributing to localized flooding.
National Flood Insurance Program (NFIP) claims data indicates that properties in Zone A have experienced the most frequent claims, with an average payout of $21,677 and an average water depth of 4.0 feet. While Zone X claims are less frequent, they have shown higher average payouts ($28,165). Homeowners in areas designated as Zone A, as well as those near creeks and in low-lying areas, should pay particular attention to flood risk.
Summary generated from NOAA storm narratives and NFIP claim data for this county. Not predictive.
21 NOAA storm reports from this county describe what happened, in the words of the meteorologists who were there.
Jefferson County, Illinois has recorded 49 flood-related events since 1996 according to NOAA's Storm Events Database, including 34 flash floods and 15 river or area floods. The county has received 5 federal disaster declarations. Enter any address above to check its FEMA flood zone designation.
FEMA Disaster Declarations (2002–2020)
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 | Severe Storm | Apr 19, 2011 |
| Hurricane Katrina Evacuation | Hurricane | Aug 29, 2005 |
| Severe Storms, Tornadoes And Flooding | Tornado | Apr 21, 2002 |
NOAA Storm Events Database (1996–2025)
Source: NOAA National Weather Service Storm Events Database.
| Type | Date | Damage |
|---|---|---|
| Flood | Jul 16, 2024 | 0.00K |
| Flash Flood | Jul 16, 2024 | 0.00K |
| Flood | Aug 1, 2024 | 0.00K |
| Flash Flood | Aug 29, 2022 | 10.00K |
| Flash Flood | Jul 26, 2022 | 0.00K |
| Flood | Sep 4, 2022 | 0.00K |
| Flood | Jul 16, 2021 | 30.00K (1 deaths) |
| Flash Flood | Mar 19, 2020 | 0.00K |
| Flood | May 29, 2019 | 0.00K |
| Flood | May 21, 2019 | 0.00K |
Flood — Jul 16, 2024
Extreme rainfall totals occurred during the morning of the 16th in and around Nashville, Illinois, just northwest of the Quad State region, which resulted in a secondary dam failure. Neighboring portions of Jefferson and Perry Counties received 3-6 and 2-5 inches, respectively. Extensive street flooding occurred in Mount Vernon, while some roads north of Tamaroa flooded for the second time with...
Flash Flood — Jul 16, 2024
Extreme rainfall totals occurred during the morning of the 16th in and around Nashville, Illinois, just northwest of the Quad State region, which resulted in a secondary dam failure. Neighboring portions of Jefferson and Perry Counties received 3-6 and 2-5 inches, respectively. Extensive street flooding occurred in Mount Vernon, while some roads north of Tamaroa flooded for the second time with...
Flood — Aug 1, 2024
A robust squall line swept through the I-64 corridor of Southern Illinois during the early afternoon hours on the 1st. Numerous wind damage reports were received, primarily in Wayne, Hamilton, and White Counties with many trees and powerlines damaged along with several farm structures. Utility data indicated that roughly half of Wayne County lost power with this storm line. MLCAPE values were a...
Flash Flood — Aug 29, 2022
An isolated severe thunderstorm drifted slowly over west central Hamilton County, producing large hail. This storm and other scattered thunderstorms developed during the heat of the day ahead of a cold front. Some of the storms produced torrential rain, which resulted in an isolated flash flood event. The cold front trailed southwest from a low pressure center over the Great Lakes region across...
Flash Flood — Jul 26, 2022
A complex of thunderstorms moved east across parts of southern Illinois through the morning. Training of heavy rain resulted in widespread 2 to 4 inches of rainfall along the Interstate 64 corridor. The persistent thunderstorms were focused along a stalled elevated warm front across the mid Mississippi Valley. Strong convergence in the 925 to 850 mb layer was oriented generally parallel to the ...
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 Jefferson 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 Jefferson 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.