Severe · Flash Flood WarningActive alert
Flash Flood Warning issued September 20 at 2:12AM 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)
FFWLOT The National Weather Service in Chicago has issued a * Flash Flood Warning for... Southern De Kalb County in north central Illinois... Northern La Salle County in north central Illinois... Lee County in north central Illinois... * Until 800 AM CDT. * At 212 AM CDT, Doppler radar indicated thunderstorms producing heavy rain across the warned area. Up to 3 inches of rain have fallen. The expected rainfall rate is 1.5 to 2.5 inches per hour. Additional rainfall amounts of 1 to 3 inches are possible in the warned area. 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™