40
Recorded events
0
Direct deaths
0
Direct injuries
$2.1M
Property damage
Flash Flood in Stephenson County, Illinois: 40 recorded events between 1997 and 2024. The strongest on record measured 0. That places the county #826 nationally and #22 statewide for this hazard.
Decade by decade
Flash Flood in Stephenson County, Illinois: events per decade
Reporting practice changed over time — early decades are undercounted, not calmer.
The busiest decade for flash flood in Stephenson County is the 2010s, when 19 of the county's 40 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 Stephenson County archive, flash flood makes up 7.7% of all recorded severe weather across 8 hazard types. Nationally the county sits at #826 for this hazard and #22 within Illinois, putting it in the 72.5 percentile of all U.S. counties.
Seasonality
Events by month
Jul is the peak month for flash flood in Stephenson County with 12 recorded events, while Jan 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.
Most recent
Latest recorded events
| Date | Location | Magnitude | Damage |
|---|---|---|---|
| Jul 15, 2024 | FREEPORT | 0 | $0 |
| Aug 8, 2022 | WADDAMS GROVE | 0 | $0 |
| Aug 8, 2022 | MC CONNELL | 0 | $0 |
| Aug 8, 2022 | MC CONNELL | 0 | $0 |
| Aug 8, 2022 | FREEPORT | 0 | $0 |
| Aug 8, 2022 | LAKE LEAQUANA | 0 | $0 |
| Aug 7, 2022 | SCIOTA MILLS | 0 | $0 |
| Sep 13, 2019 | ELEROY | 0 | $0 |
| Sep 10, 2019 | ONECO | 0 | $0 |
| Oct 6, 2018 | ROCK GROVE | 0 | $0 |
Other hazards here
More from Stephenson County
- Thunderstorm Wind 261
- Hail 135
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
Torrential rains of 3 to 8 inches caused some flash flooding across parts of Stephenson County during the evening of July 27 and morning of July 28. There were reports of cattle scattered through county by flood waters with some washed downstream. The flood waters were several feet deep in the town of Pearl City. Two people died just west of Freeport, IL from carbon monoxide fumes from a generator use to pump water from a flooded basement.
Heavy rains of 3 to 7 inches fell across Stephenson County during the early morning hours of August 7th resulting in flash flooding. Two feet of water was coving parts of Highway 20 east of Highway 73. Some motorists were stranded in high water in Freeport, IL. Several gravel roads east of the Highway 20 and Highway 73 intersection were washed out. The US Bank and Health Department buildings in Freeport had flooded basements.
The Emergency Manager reports that 6 hour rainfall has been 4 to 8 inches. They also reported that flood waters have moved into the road maintenance shed for the city of Freeport. Additionally, there were two roads washed out in county as well as widespread reports of water on area roadways. The time of the event was estimated using radar.
Quick answers
Frequently asked
How many flash flood events are on record in Stephenson County, Illinois?
40 flash flood events are recorded in Stephenson County between 1997 and 2024, causing 0 direct deaths.
What is the strongest flash flood recorded in Stephenson County?
The strongest flash flood on record in Stephenson County measured 0.
Where does the flash flood data for Stephenson 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
“Flash Flood in Stephenson County, Illinois.” Severe Weather History. severeweatherhistory.com/county/illinois/stephenson-county/flash-flood/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.