Severe · Flash Flood WarningActive alert
Flash Flood Warning issued September 20 at 5:09AM CDT until September 20
Affecting De Kalb, IL; La Salle, IL; Lee, IL
In effect until: Sep 20, 2026, 1:00 PM
De Kalb, IL; La Salle, IL; Lee, IL
Likely impact across 3 counties in IL; effects through 1:00 PM.
Get to higher ground now. Never drive through flooded roads.
Read the original bulletin (official text)
At 509 AM CDT, Doppler radar indicated thunderstorms produced heavy rain across the warned area. Between 3 and 6 inches of rain have fallen with the highest amounts across Lee County. While the heavy rain has ended, additional heavy rain is possible later this morning. Flash flooding is ongoing or expected to begin shortly. HAZARD...Flash flooding caused by thunderstorms. SOURCE...Radar indicated. IMPACT...Rapid-onset flooding of creeks, streams, drainage ditches, streets, underpasses, low-lying areas, and other poor drainage areas. Some locations that will experience flash flooding include... Sandwich, Mendota, Amboy, Sheridan, Shabbona, Lake Holiday, Hinckley, Somonauk, Earlville, Waterman, Serena, Leland, Paw Paw, Sublette, Woodhaven Lakes, Millington, Lee, Compton, Troy Grove, Nelson, West Brooklyn, Harmon, Triumph, Prairie Center and Lee Center.
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Alert data: U.S. National Weather Service / NOAA · Translation: WeatherTranslate™