Lake Superior, Great Lakes ice breaking up
The frigid winter of 2014 threw its best at Lake Superior, but the big lake was just too stubborn to freeze over completely.
Satellite photographs over the past few days show ice on Lake Superior beginning to diminish, with vast areas of open water along the North Shore and fissures developing across the lake.
"It appears that the ice cover on the Great Lakes is starting to break up and recede with the warm air temperatures and higher winds we are having,'' George Leshkevich, Great Lakes ice expert for the National Oceanic and Atmospheric Administration, told the News Tribune on Tuesday.
Lake Superior peaked at about 95 percent ice cover, both in mid-February and again in early March. But the lake ice had diminished to an estimated 91 percent on Monday, the most recent analysis.
Experts noted that lake ice developed and expanded quickly this winter when Superior appeared on the way to its first ice-over since 1996. But continued strong winds, an increasingly higher and more powerful sun angle, and a blast of warm weather in the past week thwarted those chances.
Collectively, the Great Lakes dropped from a peak of about 91 percent ice cover to an estimated 84 percent in the most recent analysis. Lakes Ontario, Michigan and Superior always held large areas of open water. Lakes Huron and Erie came closest to complete ice-over, with ice cover estimated at more than 95 percent.
Lake ice is expected to hold fast for some time at the extreme western tip and around the Apostle Islands, as well as at the eastern tip of Lake Superior and in channels and harbors.
Ensign Barton Nanney, public affairs officer aboard the Coast Guard Cutter Alder stationed in Duluth, said harbor ice averages about 3 feet thick but was up to 4 feet thick in parts of the harbor during exercises Monday. The Alder found much thinner ice on Lake Superior. The cutter easily reached open water about 7 miles out from the Aerial Lift Bridge, Nanney said.
The Soo Locks will open March 25 and, barring any ice difficulties, upper Great Lakes vessels should be moving again by that date. Great Lakes shipping interests have predicted slow going for the first days of the shipping season because of the ice.
Combined, the Great Lakes had their greatest ice coverage since the 1970s, thanks to near record low temperatures from December through February, including Duluth's second-coldest meteorological winter on record.
Leshkevich said ice on the southerly Great Lakes generally peaks in mid- to late February, while peaking in late February or early March on the upper lakes.