Special Marine Warning Issued for Southern Lake Michigan Harbors and Open Waters

Alert Details

The National Weather Service in Chicago has issued a Special Marine Warning for the nearshore and open waters of Lake Michigan. The alert was issued at 5:45 PM CDT on March 10, 2026, following reports from law enforcement regarding a severe thunderstorm moving through the region.

Affected Areas

The warning affects the following geographic regions and maritime zones:

• Nearshore Waters: Wilmette Harbor to Calumet Harbor, and Calumet Harbor to Michigan City.
• Open Waters: Winthrop Harbor to Michigan City, extending from 5 nautical miles offshore to Mid Lake.

Specific locations impacted include Harrison-Dever Crib, 31st Street Harbor, Monroe Harbor, Burns Harbor, Calumet Harbor, Indiana Harbor, Montrose Harbor, Burnham Harbor, Hammond Marina, Jackson Park Harbor, Belmont Harbor, and Marina Shores at Dune Harbor.

What You Should Do

Mariners are advised to move to safe harbor immediately. Remain in port until the hazardous weather conditions have passed. Small craft should be especially cautious as they could be damaged by suddenly higher winds and waves.

Expected Conditions

At 5:45 PM CDT, a severe thunderstorm was tracked 10 nautical miles west of Midway Airport (approximately 17 nm west of 31st Street Harbor), moving northeast at 25 knots.

• Hazards: Wind gusts of 34 knots or greater and large hail.
• Impacts: Potential for structural damage from hail and damage to small craft from elevated wind and wave activity.

Timeline

The Special Marine Warning is effective immediately and is currently set to expire at 7:45 PM CDT on March 10, 2026.