Flood Warning Issued for Grundy, La Salle, Livingston Counties in Illinois

Source: NOAA · Northern and Central Illinois

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NWS Chicago has issued a Flood Warning for parts of Illinois due to excessive rainfall, in effect until 7 AM CDT on August 10, 2026.

Read this weather record in 30 seconds

Record type
Flood Warning
Affected area
Northern and Central Illinois
Issued
August 10, 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: publication date is recent, but current status is not stored on this page. Check the issuing agency's live warning service before acting because warnings can be updated, narrowed, or cancelled.

Alert Details

Flood Warning issued by NWS Chicago IL. Effective from August 10, 2026 at 2:32 AM CDT until August 10, 2026 at 7:00 AM CDT. The alert is classified as Severe with Likely certainty.

Affected Areas

Grundy County, La Salle County, and Livingston County in Illinois. Specifically: Northeastern Livingston County in central Illinois, East Central La Salle County in north central Illinois, and Southern Grundy County in northeastern Illinois. Locations include Ottawa, Streator, Dwight, Gardner, Mazon, Grand Ridge, South Wilmington, Ransom, Verona, Campus, East Brooklyn, and Kinsman. This covers the headwaters of the Mazon River, Otter Creek, and Covel Creek.

What You Should Do

A Flood Warning means flooding is imminent or may already be occurring. Persons along rivers, creeks, and other waterways should take immediate precautions to protect life and property. Be especially cautious at night when it is harder to recognize the dangers of flooding.

Expected Conditions

Flooding caused by excessive rainfall is expected. Rainfall amounts of 2 to 3 inches occurred across the area, with rainfall in excess of 4 inches observed near Dwight. Creeks and streams may rise out of their banks. Flooding may occur in poor drainage and urban areas. Slow moving or standing water may continue. High water likely may recede slowly from flooded areas.

Timeline

The warning is in effect until 7:00 AM CDT on August 10, 2026. At 2:28 AM CDT, Doppler radar indicated heavy rainfall had moved out of the area, with water slow to recede from fields, yards, and poor drainage areas.

Original source: NOAA Official Notice ↗

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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 parts of Illinois due to excessive rainfall, in effect until 7 AM CDT on August 10, 2026.
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 Northern and Central 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.