Flash Flood Warning — Grundy County, Illinois
Flooding is imminent or already occurring. Move to higher ground immediately — never drive through flooded roads.
Current Status
🌊 Active: Flash Flood Warning
Flash Flood Warning issued August 9 at 11:47PM CDT until August 10 at 3:45AM CDT by NWS Chicago IL
FFWLOT The National Weather Service in Chicago has issued a * Flash Flood Warning for... Northeastern Livingston County in central Illinois... East Central La Salle County in north central Illinois... Southern Grundy County in northeastern Illinois... * Until 345 AM CDT. * At 1147 PM CDT, Doppler radar indicated slow moving thunderstorms with rain rates of 2 to 3 inches per hour. Up to 2.5 inches has occurred so far just north of Streator. Flash flooding is ongoing or expected to begin shortly. HAZARD...Flash flooding caused by thunderstorms. 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... Streator, Marseilles, Dwight, Seneca, Gardner, Mazon, South Streator, Braceville, Grand Ridge, South Wilmington, Ransom, Kangley, Verona, Campus, Reddick, East Brooklyn and Kinsman.
Effective August 10, 2026 at 12:47 AM ET · Expires August 10, 2026 at 4:45 AM ET
Event Details
Event Type
Flash Flood Warning
Severity
severe
Issued By
NWS Chicago IL
Expires
August 10, 2026 at 4:45 AM ET
Last Checked
1 minute ago
What To Do
📋 Official NWS Guidance
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.
Also In Effect For
This same Flash Flood Warning also covers:
Other Active Alerts in Illinois
Flood Advisory
Severe Thunderstorm Watch
Flood Advisory
Severe Thunderstorm Watch
Flash Flood Warning
Flood Advisory
Get Flash Flood Warning Alerts for Grundy County
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Frequently Asked Questions
What does a Flash Flood Warning mean for Grundy County, Illinois?
Flooding is imminent or already occurring. Move to higher ground immediately — never drive through flooded roads.
Is this Flash Flood Warning currently active?
Yes — this alert is active as of our last check (1 minute ago). It's set to expire August 10, 2026 at 4:45 AM ET.
How do I get notified about Flash Flood Warning alerts for Grundy County?
Download StormCast free on Google Play and set Grundy 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 Flash Flood Warning is also in effect for Livingston County, La Salle County.