Flood Warning Issued for Thorn Creek in Cook County Through Thursday Morning
This alert is no longer in effect.
NOAA issued it on April 6, 2026, 4 months ago. Warnings of this kind stay in effect for hours to a few days, so this page is a historical record of what was issued, not a current warning. For conditions where you are right now, check weather.gov (US), weather.gc.ca (Canada), the Met Office (UK), or the Bureau of Meteorology (Australia).
Areazine synthesizes this NWS weather alert directly from NOAA's official public data feed. See our methodology for full source attribution and refresh cadence.
The National Weather Service has issued a Flood Warning for Thorn Creek at Thornton, affecting Cook County, with minor flooding expected to crest at 9.9 feet this evening.
Read this weather record in 30 seconds
- Record type
- Flood Warning
- Affected area
- Cook County, Illinois
- Issued
- April 6, 2026
- Issuing authority
- NWS Chicago
Flood notices turn on location and timing. Treat the named area as this record's scope; do not assume nearby counties, parishes, or waterways were included.
Record status: historical. It was issued 4 months ago; use the issuing agency's live warning service for current conditions in Cook County, Illinois.
Alert Details
The National Weather Service in Chicago IL has issued a Flood Warning for Thorn Creek at Thornton. This alert indicates that minor flooding is imminent or occurring within the specified area. The warning was issued early Wednesday morning as river levels are expected to rise significantly.
Affected Areas
The warning specifically impacts Cook County, Illinois. The affected geographic scope includes Thorn Creek from near Glenwood downstream to the confluence with the Little Calumet River, including the area surrounding the Thornton gauge.
What You Should Do
Persons along rivers and streams in the warned area should take immediate precautions to protect life and property. The NWS response recommendation is to avoid the area. Residents should monitor local conditions and be prepared for rising water levels.
Expected Conditions
Minor flooding is forecast for the region. As of 1:15 AM CDT Wednesday, the river stage was recorded at 4.4 feet. The river is expected to rise above the flood stage of 9.0 feet late this morning. A crest of 9.9 feet is anticipated this evening.
At the 9.0-foot flood stage, water begins to be diverted through the Thorn Creek Diversion Tunnel. These forecasts are based on observed precipitation as well as forecast precipitation 24 hours into the future.
Timeline
The Flood Warning is effective from late Wednesday morning, March 11, through Thursday morning, March 12. The river is expected to rise above flood stage late this morning and fall below flood stage just after midnight tonight. The warning is currently scheduled to expire at 7:30 AM CDT on March 12.
Original source: NOAA Official Notice ↗
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