Illinois Severe Flash Flood Warning | Effective 09/17/2026 05:07

Headline: 
Flash Flood Warning issued September 17 at 7:07AM CDT until September 17 at 11:00AM CDT by NWS Chicago IL
Event: 
Flash Flood Warning
Urgency: 
Immediate
Effective: 
September 17, 2026 - 5:07am
Expires: 
September 17, 2026 - 9:00am
Description: 
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... Southeastern Lee County in north central Illinois... * Until 1100 AM CDT. * At 707 AM CDT, Doppler radar and automated rain gauges indicated thunderstorms producing heavy rain across the warned area. Between 2 and 4 inches of rain have fallen. Additional rainfall amounts up to 1 inch are possible in the warned area. Flash flooding is ongoing or expected to begin shortly. HAZARD...Flash flooding caused by thunderstorms. SOURCE...Radar and automated gauges. 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, Lake Holiday, Somonauk, Earlville, Leland, Paw Paw, Sublette, Woodhaven Lakes, Millington, Compton and West Brooklyn.
Instruction: 
A Flash Flood Warning means rapid-onset flooding is imminent or may already be occurring. Persons along creeks, drainage ditches, and other waterways should take immediate precautions to protect life and property.
Area Description: 
De Kalb, IL; La Salle, IL; Lee, IL
Forcast Office: 
NWS Chicago IL
Sender: 
w-nws.webmaster@noaa.gov