Severe Thunderstorm Warning — Cook County, Illinois
A thunderstorm capable of producing damaging winds of 58+ mph and/or 1-inch hail has been detected.
Current Status
⛈️ Active: Severe Thunderstorm Warning
Severe Thunderstorm Warning issued August 9 at 3:40PM CDT until August 9 at 4:30PM CDT by NWS Chicago IL
At 340 PM CDT, severe thunderstorms were located along a line extending from Lake Station to near Winfield to near Crete, moving east at 50 mph. HAZARD...70 mph wind gusts. SOURCE...Radar indicated. IMPACT...Expect considerable tree damage. Damage is likely to mobile homes, roofs, and outbuildings. Locations impacted include... Hammond, Gary, Portage, Merrillville, Valparaiso, East Chicago, Schererville, Hobart, Crown Point, Highland, Munster, Chesterton, Cedar Lake, Steger, Griffith, Dyer, St. John, Lake Station, Sauk Village, Lynwood, Crete, Lakes of the Four Seasons, South Haven, Porter, and Winfield.
Effective August 9, 2026 at 4:40 PM ET · Expires August 9, 2026 at 5:30 PM ET
Event Details
Event Type
Severe Thunderstorm Warning
Severity
severe
Issued By
NWS Chicago IL
Expires
August 9, 2026 at 5:30 PM ET
Last Checked
36 minutes ago
What To Do
📋 Official NWS Guidance
For your protection move to an interior room on the lowest floor of a building. Torrential rainfall is occurring with these storms, and may lead to flash flooding. Do not drive your vehicle through flooded roadways.
Other Active Alerts in Illinois
Flood Advisory
Flood Advisory
Flood Advisory
Severe Thunderstorm Watch
Flood Advisory
Flood Advisory
Get Severe Thunderstorm Warning Alerts for Cook County
StormCast checks the NWS feed continuously and pushes alerts like this directly to your phone — even with the screen off.
Frequently Asked Questions
What does a Severe Thunderstorm Warning mean for Cook County, Illinois?
A thunderstorm capable of producing damaging winds of 58+ mph and/or 1-inch hail has been detected.
Is this Severe Thunderstorm Warning currently active?
Yes — this alert is active as of our last check (36 minutes ago). It's set to expire August 9, 2026 at 5:30 PM ET.
How do I get notified about Severe Thunderstorm Warning alerts for Cook County?
Download StormCast free on Google Play and set Cook 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.