ST. IGNACE — Ice has formed on the upper cables and towers of the Mackinac Bridge, creating the possibility the bridge could be closed to traffic in coming days or weeks because of falling ice, the Mackinac Bridge Authority said.
The Mackinac Bridge Authority closes the bridge to traffic when ice falls from the bridge’s towers and cables, citing safety concerns.
Ice chunks, sheets and spears that fall hundreds of feet from the bridge’s towers and cables have damaged vehicles and have the potential to injure or kill vehicle occupants.
“It’s impossible to say when this ice could begin falling from the bridge, resulting in a closure, or if it could gradually melt without incident,” Bridge Director Kim Nowack said. “We want our customers to be aware of the possibility of closures and know how to find more information if they occur.”
Since 1995, when the Mackinac Bridge Authority began tracking closures of the bridge for any reason, the bridge has closed 32 times for falling ice, about once each year on average. The first noted closure for falling ice was Jan. 30, 1998, when the bridge was closed for two hours and 50 minutes, and the most recent was April 2-3, 2025.
The shortest closure for falling ice was 37 minutes on Nov. 29, 2001. The longest closure to date was April 2-3, 2025, when the bridge was closed for 30 hours and four minutes.
The average falling ice closure lasts about five hours and 54 minutes. Over the last 30 years, the bridge has been closed 188 hours and four minutes for falling ice, less than 0.1 percent of the time.
A video released by the Mackinac Bridge Authority and the Michigan Department of Transportation includes footage and still images of kitchen table-sized sheets and 20-foot-long spears of ice shattering on the bridge deck to explain why the bridge must be closed when ice is falling.
Mackinac County 911, using its RAVE Alert System, will send updates and information from the Mackinac Bridge Authority to users’ cell phones any time the bridge has a partial or full closure due to weather or other conditions. Messages also will be sent when a full closure is reduced to a partial closure or when the bridge reopens to all traffic. To sign up, text “MacBridge” to 67283.