Severe ice conditions and a shortage of operational icebreakers have brought shipping operations on the U.S. Great Lakes to a standstill. The Soo Locks, crucial for accessing Lake Superior, are open, but the U.S.-flagged commercial fleet is trapped in the St. Marys River and Whitefish Bay, vital waterways that connect Lake Superior to the other Great Lakes. The U.S. Coast Guard's only heavy icebreaker, the Mackinaw, is out of service due to an engineering issue, leaving American vessels stranded. A Canadian icebreaker briefly assisted but was recalled to aid Canadian ships, further complicating matters for U.S. vessels.