Flood Warning Issued for Cook County, IL

Source: NOAA · Cook County, Illinois

This alert is no longer in effect.

NOAA issued it on July 8, 2026, 6 weeks 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.

NWS Chicago has issued a Flood Warning for Thorn Creek in Cook County with minor flooding forecast from late tonight to early Saturday morning.

Read this weather record in 30 seconds

Record type
Flood Warning
Affected area
Cook County, Illinois
Issued
July 8, 2026
Issuing authority
NWS Chicago IL

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 6 weeks ago; use the issuing agency's live warning service for current conditions in Cook County, Illinois.

Alert Details

A Flood Warning has been issued by NWS Chicago IL for rivers in Illinois. The alert was sent at 9:47PM CDT on June 11, 2026, and is effective from late tonight.

Affected Areas

Thorn Creek at Thornton affecting Cook County. The area includes Thorn Creek from near Glenwood downstream to confluence with Little Calumet River, including the Thornton gauge.

What You Should Do

A Flood Warning means water levels above flood stage are imminent or may already be occurring. Persons along rivers and streams in the warned area should take immediate precautions to protect life and property.

Expected Conditions

Minor flooding is forecast. At 9:30 PM CDT Thursday the stage was 8.3 feet. Flood stage is 9.0 feet. At 8.0 feet, athletic fields are inundated at Glenwood Academy. At 9.0 feet, water begins to be diverted through Thorn Creek Diversion Tunnel.

Timeline

The warning is in effect from late tonight (onset June 12 at 1:00AM CDT) to early Saturday morning (ends June 13 at 1:00AM CDT). The river is expected to rise above flood stage around midnight tonight and crest near 9.5 feet tomorrow morning.

Original source: NOAA Official Notice ↗

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Two Areazine-derived peer sets for this NWS weather alert: nearest notices by body length and by same severity near the same agency date. Peers come from other categories so they are not the same-feed Related list above.

Frequently Asked Questions

Common questions about this NWS weather alert.

What is this NWS weather alert about?
NWS Chicago has issued a Flood Warning for Thorn Creek in Cook County with minor flooding forecast from late tonight to early Saturday morning.
Which agency issued this alert?
This alert was issued by NOAA. The original notice is available at the source link at the bottom of this article.
How severe is this alert?
This alert is classified as "high" severity. Take precautions and monitor for updates.
What area is affected?
This alert affects Cook County, Illinois. Check with NOAA for the most current geographic scope.
Where can I find more Weather Alerts updates?
Browse the full Weather Alerts feed on Areazine at areazine.com/weather/ for the latest updates from NOAA and other agencies.