Flood Advisory — De Kalb County, Illinois
Minor flooding is expected — not severe enough for a warning, but potentially inconvenient or hazardous for travel.
Current Status
🌊 Active: Flood Advisory
Flood Advisory issued August 9 at 11:32PM CDT until August 10 at 2:30AM CDT by NWS Chicago IL
* WHAT...Flooding caused by excessive rainfall is expected. * WHERE...Southwestern De Kalb County in north central Illinois... La Salle County in north central Illinois... * WHEN...Until 230 AM CDT. * IMPACTS...Creeks and streams may rise out of their banks. Roads and streets may be flooded. * ADDITIONAL DETAILS... - At 1131 PM CDT, Doppler radar indicated slow moving thunderstorms producing rainfall rates of 1 to 2 inches per hour. Up to 1.5 inches of rain have fallen so far near Grand Ridge. Minor flooding is ongoing or expected to begin shortly in the advisory area. - Some locations that will experience flooding include... Ottawa, Streator, Peru, La Salle, Sandwich, Mendota, Marseilles, Sheridan, Shabbona, Lake Holiday, Oglesby, Seneca, Somonauk, Earlville, Waterman, North Utica, Serena, Leland, Tonica and Grand Ridge. - http://www.weather.gov/safety/flood
Effective August 10, 2026 at 12:32 AM ET · Expires August 10, 2026 at 3:30 AM ET
Event Details
Event Type
Flood Advisory
Severity
minor
Issued By
NWS Chicago IL
Expires
August 10, 2026 at 3:30 AM ET
Last Checked
just now
What To Do
📋 Official NWS Guidance
A Flood Advisory means minor flooding along waterways and other poor drainage areas is imminent or may already be occurring. Persons in the advisory area should use caution and avoid flood waters.
Other Active Alerts in Illinois
Severe Thunderstorm Watch
Severe Thunderstorm Watch
Tornado Warning
Severe Thunderstorm Watch
Severe Thunderstorm Watch
Severe Thunderstorm Watch
Get Flood Advisory Alerts for De Kalb County
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Frequently Asked Questions
What does a Flood Advisory mean for De Kalb County, Illinois?
Minor flooding is expected — not severe enough for a warning, but potentially inconvenient or hazardous for travel.
Is this Flood Advisory currently active?
Yes — this alert is active as of our last check (just now). It's set to expire August 10, 2026 at 3:30 AM ET.
How do I get notified about Flood Advisory alerts for De Kalb County?
Download StormCast free on Google Play and set De Kalb County, Illinois as one of your monitored locations. StormCast checks the NWS feed continuously and pushes alerts like this directly to your phone — even with the screen off.