Oddly, Superior is already ice-free

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If you like to ice fish for lake trout off the North Shore of Lake Superior or trek to the sea caves at Apostle Islands, this wasn’t your winter.

Warmer than normal air translated to warmer water conditions, leading to an unusually small amount of ice on the big lake and, in many areas, no ice at all.

The last week in February and first week in March are typically the period for peak ice coverage on Lake Superior.

But satellite photographs taken over the past week show virtually no ice on the open portions of the lake. The small amount of drifting pack ice outside the Twin Ports can be seen in the photos, as can frozen-over Chequamegon Bay and Thunder Bay.

The National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory in Ann Arbor, Mich., reported Tuesday that Lake Superior’s ice cover was in the lowest 25th percentile of its long-term average.

Ice coverage peaked Feb. 23 at just over 27 percent of the lake’s surface area. That compares to nearly 89 percent peak ice coverage on March 2 last winter, which was much colder, and more than 60 percent in an “average” winter.

The core winter months of December, January and February saw temperatures 1.3 degrees above normal on average in Duluth. But if you factor in November and the first week of March, both of which were 10 degrees above normal, the region has seen a veritably balmy ice season.

The warmest November in more than 100 years may have been the biggest factor.

“Wind makes some difference … but the temperature of the lake and the air temperatures are the biggest factors,” said George Leshkevich, NOAA research scientist. “If you don’t get the cold temperatures early on in the winter, the lake has a tremendous ability to retain heat and, unless you get very cold temperatures later in the winter, the ice never gets a chance to form.”

With a normal amount of sunshine this spring and summer, Lake Superior could see some unusually balmy water temperatures later this year thanks to the “jump start” from the lack of ice, Leshkevich said.

“But it all depends on the solar warming. If you have a cloudy, cool spring, that effect would be lost,” he said.

Neil Howk of Apostle Islands National Lakeshore said safe ice never formed this winter for visitors to tour the park’s famous mainland sea caves. Last year there were nearly eight weeks of safe ice.

“We had a couple good years (2008 and 2009), but the trend has been fewer and fewer days where there’s enough ice to get out there,” Howk said. “We thought we had it on Feb. 4 this year … then the wind switched and the ice blew out and it never came back.”

Tags: two harbors, news, ice, lake superior