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Flood in LaSalle County, Illinois
77 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 77 flood events in LaSalle County, Illinois, between 1950 and 2026, spread over 25 years.
May is the busiest month, with 17 of the recorded events. The last 20 years account for 62 events against 15 in the 20 years before, a change that reflects reporting practice as much as weather.
The county holds 1.2% of the 6,507 flood events recorded in Illinois; its 6.8 per 100 square miles compares with 11.7 statewide.
NCEI attributes 1 death in the county to floods and flash floods.
Compared with Illinois
| Measure | LaSalle County | Illinois | US |
|---|---|---|---|
| Flood events since 1950 | 77 | 6,507 | 183,559 |
| Per 100 square miles | 6.8 | 11.7 | 5.2 |
| Per 10,000 residents | 7.1 | 5.1 | 5.5 |
| Deaths recorded | 1 | 61 | 2,961 |
| Busiest month | May | June | June |
By year
Seasonality
5Feb
4Mar
1Apr
7May
17Jun
11Jul
10Aug
13Sep
8Oct
1Nov
0Dec
0
Recorded events
All 77 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 | — | — | — | — | — | County |
| 17 Aug 2025 | Flash Flood | — | — | — | — | — | County |
| 17 Aug 2025 | Flash Flood | — | — | — | — | — | County |
| 31 Jan 2025 | Flood | — | — | — | — | — | County |
| 10 Jul 2024 | Flood | — | — | — | — | — | County |
| 28 Apr 2024 | Flood | — | — | — | — | — | County |
| 27 Jan 2024 | Flood | — | — | — | — | — | County |
| 16 Jan 2024 | Flood | — | — | — | — | — | County |
| 7 May 2023 | Flood | — | — | — | — | — | County |
| 22 Feb 2022 | Flood | — | — | — | — | — | County |
| 18 Feb 2022 | Flood | — | — | — | — | — | County |
| 13 Jul 2021 | Flood | — | — | — | — | — | County |
| 12 Jul 2021 | Flash Flood | — | $1.2M | — | — | — | County |
| 17 May 2020 | Flood | — | — | — | — | — | County |
| 28 Sep 2019 | Flood | — | — | — | — | — | County |
| 27 Sep 2019 | Flash Flood | — | — | — | — | — | County |
| 27 Sep 2019 | Flash Flood | — | — | — | — | — | County |
| 1 May 2019 | Flood | — | — | — | — | — | County |
| 20 Feb 2018 | Flood | — | — | — | — | — | County |
| 21 Jul 2017 | Flood | — | — | — | — | — | County |
| 30 Aug 2016 | Flood | — | $2K | — | — | — | County |
| 12 Aug 2016 | Flash Flood | — | — | — | — | — | County |
| 18 Sep 2015 | Flash Flood | — | — | — | — | — | County |
| 13 Jun 2015 | Flash Flood | — | $100K | — | — | — | County |
| 13 Jun 2015 | Flash Flood | — | — | — | — | — | County |
| 18 Apr 2013 | Flash Flood | — | $75M | — | 1 | — | County |
| 17 Apr 2013 | Flash Flood | — | — | — | — | — | County |
| 6 May 2012 | Flash Flood | — | — | — | — | — | County |
| 6 May 2012 | Flood | — | — | — | — | — | County |
| 8 Aug 2011 | Flash Flood | — | $2K | — | — | — | County |
| 21 Jun 2011 | Flood | — | $50K | — | — | — | County |
| 21 Jun 2011 | Flood | — | — | — | — | — | County |
| 20 Jun 2011 | Flash Flood | — | — | — | — | — | County |
| 20 Jun 2011 | Flash Flood | — | $75K | — | — | — | County |
| 25 May 2011 | Flood | — | — | — | — | — | County |
| 25 May 2011 | Flash Flood | — | — | — | — | — | County |
| 25 May 2011 | Flash Flood | — | — | — | — | — | County |
| 25 May 2011 | Flood | — | — | $20K | — | — | County |
| 14 May 2011 | Flood | — | — | — | — | — | County |
| 19 Apr 2011 | Flood | — | — | — | — | — | County |
| 2 Jun 2010 | Flash Flood | — | $10K | — | — | — | County |
| 19 Aug 2009 | Flood | — | — | — | — | — | County |
| 24 Jul 2009 | Flood | — | — | — | — | — | County |
| 15 May 2009 | Flood | — | — | — | — | — | County |
| 15 May 2009 | Flood | — | — | — | — | — | County |
| 15 May 2009 | Flash Flood | — | — | — | — | — | County |
| 27 Apr 2009 | Flood | — | — | — | — | — | County |
| 15 Sep 2008 | Flood | — | $5.0M | — | — | — | County |
| 14 Sep 2008 | Flood | — | $15K | — | — | 5 | County |
| 14 Sep 2008 | Flash Flood | — | $5.0M | — | — | — | County |
| 13 Sep 2008 | Flash Flood | — | — | — | — | — | County |
| 12 Jul 2008 | Flash Flood | — | $150K | — | — | — | County |
| 17 Feb 2008 | Flood | — | $100K | — | — | — | County |
| 8 Jan 2008 | Flash Flood | — | — | — | — | — | County |
| 8 Jan 2008 | Flood | — | — | — | — | — | County |
| 24 Aug 2007 | Flood | — | $1.0M | — | — | — | County |
| 23 Aug 2007 | Flood | — | — | — | — | — | County |
| 23 Aug 2007 | Flash Flood | — | $250K | — | — | — | County |
| 23 Aug 2007 | Flood | — | — | — | — | — | County |
| 19 Aug 2007 | Flash Flood | — | — | — | — | — | County |
| 26 Jun 2007 | Flood | — | — | — | — | — | County |
| 23 Mar 2007 | Flood | — | — | — | — | — | County |
| 10 Aug 2006 | Flood | — | — | — | — | — | County |
| 29 May 2006 | Flash Flood | — | $10K | — | — | — | County |
| 16 Apr 2006 | Flash Flood | — | $25K | — | — | — | County |
| 16 Apr 2006 | Flash Flood | — | — | — | — | — | County |
| 30 May 2004 | Flash Flood | — | — | — | — | — | County |
| 30 May 2004 | Flash Flood | — | — | — | — | — | County |
| 4 Jun 2002 | Flash Flood | — | — | — | — | — | County |
| 12 May 2002 | Flood | — | — | — | — | — | County |
| 3 Jul 2001 | Flood | — | — | — | — | — | County |
| 10 Jul 2000 | Flash Flood | — | — | — | — | — | County |
| 17 Oct 1998 | Flood | — | — | — | — | — | County |
| 6 Jul 1998 | Flood | — | — | — | — | — | County |
| 16 Jun 1998 | Flash Flood | — | — | — | — | — | County |
| 17 Jul 1996 | Flash Flood | — | — | — | — | — | County |
| 6 Jun 1996 | Flash Flood | — | — | — | — | — | County |
Questions and answers
How many flood events has LaSalle County had?
77 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 LaSalle 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 LaSalle County?
The flash flood of 18 Apr 2013, with property damage estimated by NCEI at $75M; 1 death recorded.
How does LaSalle County compare with Illinois for flood?
6.8 events per 100 square miles against 11.7 statewide; the county holds 77 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.