Winter weather conditions temporarily close Mackinac Bridge to traffic

The Mackinac Bridge, which connects the two peninsulas of Michigan over the Straits of Mackinac, was closed to all traffic starting at 10:37 a.m. Friday morning. 

The cause was poor visibility related to winter weather conditions. 

"The Mackinac Bridge Authority is monitoring conditions at various points along the structure. When conditions improve, the bridge will be reopened to traffic," the bridge authority said.   

The National Weather Service says a winter storm warning is in effect for much of the Upper Peninsula, along with the very northern section of the Lower Peninsula, during the day Friday until early Saturday. "Power outage and tree damage are likely due to the ice. Travel could be nearly impossible," the NWS in Gaylord said in its Friday morning forecast. 

Another brewing storm system has spurred a winter storm watch for that region of Michigan, for late Saturday night through Monday evening. 

In addition to poor visibility, there has been a concern in recent days over falling ice. The bridge authority issued a statement Thursday saying that about a half-inch of ice has formed on the upper cables and towers of the bridge. 

"Temperatures are predicted to remain below freezing in the Straits for the next several days, but gusty winds have the potential to loosen accumulated ice," the authority said. 

The bridge has already closed for falling ice four times this winter, between Feb. 19 and Feb. 22. An ice-related closure happens an average of once a year and lasts a few hours each time, the bridge authority said.  

In many cases, the ice gradually melts and does not cause a hazard. 

The five-mile bridge opened in 1957 and is a cherished landmark in addition to providing a crucial transportation link for traffic on Interstate 75.