41
Recorded events
0
Direct deaths
5
Direct injuries
$6.2M
Property damage
Flood in LaSalle County, Illinois: 41 recorded events between 1998 and 2025. The strongest on record measured 0. That places the county #317 nationally and #15 statewide for this hazard.
Decade by decade
Flood in LaSalle County, Illinois: events per decade
Reporting practice changed over time — early decades are undercounted, not calmer.
The busiest decade for flood in LaSalle County is the 2000s, when 17 of the county's 41 recorded events were logged. Comparing decades is useful for spotting active periods, but the earliest years are thin because systematic reporting for this hazard began later.
Within the LaSalle County archive, flood makes up 5.4% of all recorded severe weather across 8 hazard types. Nationally the county sits at #317 for this hazard and #15 within Illinois, putting it in the 88.9 percentile of all U.S. counties.
Seasonality
Events by month
May is the peak month for flood in LaSalle County with 10 recorded events, while Nov is the quietest. Seasonality here is a property of the archive as much as the climate: reports cluster where population and spotter networks are densest.
Significant events
Deadliest on record
| Date | Location | Scale | Deaths | Injuries | Damage |
|---|---|---|---|---|---|
| Sep 14, 2008 | LAKE HOLIDAY | 0 | 0 | 5 | $15K |
Most recent
Latest recorded events
| Date | Location | Magnitude | Damage |
|---|---|---|---|
| Jan 31, 2025 | MENDOTA | 0 | $0 |
| Jul 10, 2024 | STREATOR | 0 | $0 |
| Apr 28, 2024 | RUTLAND | 0 | $0 |
| Jan 27, 2024 | OTTAWA | 0 | $0 |
| Jan 16, 2024 | NAPLATE | 0 | $0 |
| May 8, 2023 | SERENA | 0 | $0 |
| Feb 22, 2022 | NAPLATE | 0 | $0 |
| Feb 18, 2022 | WILSMAN | 0 | $0 |
| Jul 13, 2021 | SENECA | 0 | $0 |
| May 17, 2020 | SENECA | 0 | $0 |
Other hazards here
More from LaSalle County
- Thunderstorm Wind 390
- Hail 175
- Tornado 64
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
The Illinois River reached a record crest of 33.79 feet at LaSalle on the 16th. Major flooding occurred along the river in LaSalle County. In Marseilles, flood waters inundated Illini State Park and nearby areas. Flood waters inundated the Peru power plant. Brunner and Water Streets were closed due to flooding. Navigation on the river was halted as most lock facilities were submerged. The Interstate 39 bridge was the only one open as State Highways 251, 351, and 178 were closed. Homes and businesses in Utica were flooded. In Ottawa, 89 residents of a nursing home were evacuated. Dee Bennett Road between Ottawa and Utica was closed. Central Elementary School in Ottawa was surrounded by water and the auditorium was flooded with 8 inches of water.
Heavy rain throughout the month over southern Wisconsin and northern Illinois caused the Fox River to crest at 17.33 feet at Dayton on August 24. This was more than 5 feet above flood stage. Basements and garages were flooded along the river in Wedron and Ottawa.
Widespread flooding across parts of La Salle County slowly receded through September 17th. Five teenagers were injured on the evening of September 14th when the driver of the vehicle they were in, lost control on a water covered road. The car entered a ditch and flipped over.
Quick answers
Frequently asked
How many flood events are on record in LaSalle County, Illinois?
41 flood events are recorded in LaSalle County between 1998 and 2025, causing 0 direct deaths.
What is the strongest flood recorded in LaSalle County?
The strongest flood on record in LaSalle County measured 0.
Where does the flood data for LaSalle County come from?
All events come from the NOAA/NCEI Storm Events Database, the federal public-domain archive of severe weather reports. Dates are UTC, damage is as reported and not inflation-adjusted, and the most recent entries may still be revised.
Cite this page
“Flood in LaSalle County, Illinois.” Severe Weather History. severeweatherhistory.com/county/illinois/lasalle-county/flood/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.