Flood Warning Issued for Lake and McHenry Counties in Illinois

Source: NOAA · Northeastern Illinois

This alert is no longer in effect.

NOAA issued it on April 27, 2026, 3 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.

A Flood Warning is in effect for Lake and McHenry counties in Illinois until April 25, 2026, due to excessive rainfall expected to cause flooding along the Fox River Chain of Lakes.

Read this weather record in 30 seconds

Record type
Flood Warning
Affected area
Northeastern Illinois
Issued
April 27, 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 3 months ago; use the issuing agency's live warning service for current conditions in Northeastern Illinois.

Alert Details

A Flood Warning has been issued by the National Weather Service (NWS) Chicago IL. It is effective from April 18, 2026, at 2:20 PM CDT until April 25, 2026, at 1:00 PM CDT.

Affected Areas

The warning affects Lake and McHenry counties in Illinois, specifically areas along the Fox River Chain of Lakes, including Nippersink Lake, Fox Lake, Pistakee Lake, Petite Lake, Lake Marie, Channel Lake, and Lake Catherine.

What You Should Do

Residents should prepare for flooding by moving valuables to higher ground and taking precautions to protect property. Turn around and do not drive through flooded roads.

Expected Conditions

Flooding caused by excessive rainfall is expected, with water levels potentially reaching major flood stage and remaining above flood stage for several weeks. Impacts may be similar to those in May 1973, October 1986, and June 2008.

Timeline

The alert is effective from April 18, 2026, at 2:20 PM CDT and ends on April 25, 2026, at 1:00 PM CDT.

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?
A Flood Warning is in effect for Lake and McHenry counties in Illinois until April 25, 2026, due to excessive rainfall expected to cause flooding along the Fox River Chain of Lakes.
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 Northeastern 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.