Illinois Flash Flood Warning | Effective 04/17/2026 18:12

Headline: 
Flash Flood Warning issued April 17 at 8:12PM CDT until April 18 at 2:00AM CDT by NWS Chicago IL
Event: 
Flash Flood Warning
Urgency: 
Immediate
Effective: 
April 17, 2026 - 6:12pm
Expires: 
April 18, 2026 - 12:00am
Description: 
FFWLOT The National Weather Service in Chicago has issued a * Flash Flood Warning for... Boone County in north central Illinois... Lake IL County in northeastern Illinois... McHenry County in northeastern Illinois... * Until 200 AM CDT. * At 812 PM CDT, Doppler radar indicated thunderstorms producing extremely heavy rain across and moving into the warned area. These storms will produce rainfall rates up to an inch in less 30 minutes. Additional rainfall amounts of 1 to locally over 2 inches are expected in the warned area. Flash flooding is ongoing or expected to begin shortly. HAZARD...Flash flooding. SOURCE...Radar. 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... Waukegan, Arlington Heights, Palatine, Buffalo Grove, Crystal Lake, Wheeling, Northbrook, North Chicago, Gurnee, Mundelein, Algonquin, Highland Park, Lake in the Hills, Round Lake Beach, McHenry, Belvidere, Vernon Hills, Woodstock, Zion and Huntley.
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: 
Boone, IL; Lake, IL; McHenry, IL
Forcast Office: 
NWS Chicago IL
Sender: 
w-nws.webmaster@noaa.gov