Flood Advisory — Cook 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 2:38PM CDT until August 9 at 5:15PM CDT by NWS Chicago IL
* WHAT...Flooding caused by excessive rainfall continues. * WHERE...East Central Cook County in northeastern Illinois... Southern DuPage County in northeastern Illinois... Northwestern Will County in northeastern Illinois... * WHEN...Until 515 PM CDT. * IMPACTS...Creeks and streams may rise out of their banks. Flooding may occur in poor drainage and urban areas. Underpasses may be flooded. Roads and streets may be flooded. Slow moving or standing water may continue. * ADDITIONAL DETAILS... - At 235 PM CDT, a National Weather Service meteorologist observed several inches of flowing water across roadways in downtown Naperville due to heavy rain from ongoing thunderstorms. Across the advisory area, minor flooding is ongoing or expected to begin shortly. Between 0.5 and 2 inches of rain have fallen. - Additional rainfall amounts of 0.5 to 1.5 inches are expected over the area. This additional rain will result in minor flooding. - Some locations that will experience flooding include...
Effective August 9, 2026 at 3:38 PM ET · Expires August 9, 2026 at 6:15 PM ET
Event Details
Event Type
Flood Advisory
Severity
minor
Issued By
NWS Chicago IL
Expires
August 9, 2026 at 6:15 PM 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. Turn around, don't drown when encountering flooded roads. Most flood deaths occur in vehicles.
Also In Effect For
This same Flood Advisory also covers:
Other Active Alerts in Illinois
Severe Thunderstorm Watch
Flood Advisory
Severe Thunderstorm Watch
Flood Advisory
Severe Thunderstorm Warning
Severe Thunderstorm Warning
Get Flood Advisory Alerts for Cook County
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Frequently Asked Questions
What does a Flood Advisory mean for Cook 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 9, 2026 at 6:15 PM ET.
How do I get notified about Flood Advisory alerts for Cook County?
Download StormCast free on Google Play and set Cook 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.
What other areas does this alert cover?
This same Flood Advisory is also in effect for Will County, DuPage County.