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Flood in Lee County, Illinois
31 floods and flash floods events in the NCEI Storm Events record, 1950 to 2026. Event types counted: Flood, Flash Flood, Coastal Flood, Lakeshore Flood.
NCEI notes that Storm Data is compiled from a variety of sources including the National Weather Service, other federal, state and local agencies, the media and the public; that property and crop damage figures are estimates; and that some events are recorded by NWS forecast zone rather than by county. FEMA notes that NFIP claim records are redacted and aggregated to protect the privacy of policyholders. Storm records through 30 Jun 2026.
NCEI records 31 flood events in Lee County, Illinois, between 1950 and 2026, spread over 16 years.
June is the busiest month, with 10 of the recorded events. The last 20 years account for 24 events against 7 in the 20 years before, a change that reflects reporting practice as much as weather.
The county holds 0.5% of the 6,507 flood events recorded in Illinois; its 4.3 per 100 square miles compares with 11.7 statewide.
Compared with Illinois
| Measure | Lee County | Illinois | US |
|---|---|---|---|
| Flood events since 1950 | 31 | 6,507 | 183,559 |
| Per 100 square miles | 4.3 | 11.7 | 5.2 |
| Per 10,000 residents | 9.1 | 5.1 | 5.5 |
| Deaths recorded | 0 | 61 | 2,961 |
| Busiest month | June | June | June |
By year
Seasonality
1Feb
1Mar
1Apr
0May
5Jun
10Jul
4Aug
5Sep
2Oct
1Nov
0Dec
1
Recorded events
All 31 events, most recent first. Magnitude is hail size, tornado rating or wind speed as recorded.
| Date | Event type | Magnitude | Property damage | Crop damage | Deaths | Injuries | Geography |
|---|---|---|---|---|---|---|---|
| 18 Aug 2025 | Flash Flood | — | — | $5K | — | — | County |
| 27 Jun 2020 | Flood | — | — | — | — | — | County |
| 27 Jun 2020 | Flash Flood | — | — | — | — | — | County |
| 27 Jun 2020 | Flash Flood | — | — | — | — | — | County |
| 14 May 2020 | Flood | — | — | — | — | — | County |
| 21 Jan 2020 | Flood | — | — | — | — | — | County |
| 30 May 2019 | Flood | — | — | — | — | — | County |
| 6 Mar 2019 | Flood | — | — | — | — | — | County |
| 29 Aug 2016 | Flash Flood | — | $2K | — | — | — | County |
| 18 Aug 2016 | Flash Flood | — | — | — | — | — | County |
| 11 May 2016 | Flash Flood | — | — | — | — | — | County |
| 22 Jun 2015 | Flash Flood | — | — | — | — | — | County |
| 4 Aug 2014 | Flood | — | — | — | — | — | County |
| 30 Jun 2014 | Flash Flood | — | — | — | — | — | County |
| 9 Jun 2011 | Flood | — | — | — | — | — | County |
| 29 May 2011 | Flash Flood | — | — | — | — | — | County |
| 23 Jun 2010 | Flash Flood | — | — | — | — | — | County |
| 13 May 2010 | Flash Flood | — | $10K | — | — | — | County |
| 27 Dec 2008 | Flash Flood | — | — | — | — | — | County |
| 13 Sep 2008 | Flash Flood | — | — | — | — | — | County |
| 10 Jul 2008 | Flood | — | — | — | — | — | County |
| 23 Aug 2007 | Flash Flood | — | — | — | — | — | County |
| 18 Jul 2007 | Flash Flood | — | — | — | — | — | County |
| 18 Jul 2007 | Flood | — | — | — | — | — | County |
| 4 Sep 2006 | Flash Flood | — | — | — | — | — | County |
| 4 Jun 2002 | Flood | — | — | — | — | — | Forecast zone |
| 4 Jun 2002 | Flash Flood | — | — | — | — | — | County |
| 12 Jun 2000 | Flood | — | — | — | — | — | Forecast zone |
| 17 Oct 1998 | Flood | — | — | — | — | — | County |
| 20 Feb 1997 | Flood | — | — | — | — | — | Forecast zone |
| 17 Jul 1996 | Flash Flood | — | — | — | — | — | County |
Questions and answers
How many flood events has Lee County had?
31 events in the NCEI Storm Events record between 1950 and 2026. Reporting of floods and flash floods became far more complete after 1996, so early decades undercount.
When was the last recorded flood event in Lee County?
18 Aug 2025 (Flash Flood). Records reach NCEI about 120 days after the month ends.
What was the most damaging flood event recorded in Lee County?
The flash flood of 13 May 2010, with property damage estimated by NCEI at $10K.
How does Lee County compare with Illinois for flood?
4.3 events per 100 square miles against 11.7 statewide; the county holds 31 of the state's 6,507 recorded events.
Provenance
NOAA NCEI Storm Events Database, yearly details files through 30 Jun 2026, public domain. County-recorded events plus zone-recorded events whose forecast zone is named for the county (marked "Forecast zone"). Population and area from the US Census Bureau (2021). Built 1 Oct 2026. See the methodology, the Flood hub and the county page.