Lake Superior ice stifled by warm January
February is key, but all the Great Lakes are well behind normal ice formation.
DULUTH — An unusually warm January has left Lake Superior and the rest of the Great Lakes mostly ice free.
As of Wednesday, Lake Superior was just 11% ice covered, according to estimates by the Great Lakes Environmental Research Laboratory. Usually, by this point in February, Lake Superior would be about 35% ice covered.
All told, only about 13.5% of the Great Lakes is covered by ice compared to about 35% on average by this point of February.
A satellite photograph taken Wednesday shows most of Lake Superior entirely ice free. Thunder Bay, Chequamegon Bay and the Twin Ports harbor show solid ice. But even the usually iced-covered areas of the Apostle Islands don’t show as much solid ice, called "fast ice," as usual. The Madeline Island Ferry was still running this week because ice between Bayfield and LaPointe still isn't thick enough for safe travel by vehicles.
Ice formation on the Great Lakes is pretty simple, entirely driven by air temperature and wind. Cold, calm nights form more ice. The results have little to do with how warm the lake’s water was heading into winter as all of that energy has dissipated by now. The average temperature in Duluth in January was 17.7 degrees, according to National Weather Service data, 6.5 degrees warmer than normal, keeping the big lake’s water temperatures above the freezing point.
So far, no skating off Duluth, no trekking to ice caves
For Lake Superior, February is usually the month when major ice formation occurs, on average increasing from about 20% to nearly 50% ice cover over the month. Peak ice cover — a bit more than 50% of the lake covered on average — usually occurs in early March. But a warm February can thwart ice formation and keep much of the lake open.
Will there be ice this winter for fishing and skating off the Twin Ports’ Lake Superior shore, as there was last year? Or safe ice to the ice caves near Cornucopia on Wisconsin’s South Shore?
Not yet, and those will be up to February temperatures. So far, it’s not looking good. There is little solid ice at the western tip of the lake and the forecast calls for above-normal and even above-freezing temperatures for the next week or more.
More open water in winter can mean more evaporation from Lake Superior, which would reduce water levels. As of Feb. 1, Lake Superior was 7.5 inches higher than average for the date and was a foot above the Feb. 1 level of 2022, according to the International Lake Superior Board of Control.
Open water also can mean more chances for lake-effect snow when cold winds blow across the relatively warm surface waters of the lake.