Great Lakes have most ice in decades thanks to bitter winter

Jan 29, 2014

This winter's frigid temperatures have produced the largest amount of ice cover on the Great Lakes in at least 25 years.

Roughly 60 percent of the lakes are now under a cover of , according to the Great Lakes Environmental Research Laboratory in Ann Arbor, Mich.

The ice cover could help lake levels this summer, but that is far from certain. And biologists are keeping a close eye on northern Lake Superior in the hope that an ice bridge will link Ontario to Isle Royale.

The island is the home to a struggling gray wolf population in desperate need of new genetic stock - and more wolves.

One possible effect of so much ice this winter is that come summer the "lake effect" in cities like Milwaukee, Chicago and Duluth could be even cooler.

The ice cover this winter is a stark contrast to last winter, when the five lakes had only 38 percent cover, according to the research laboratory, which tracks ice conditions on the lakes. The long-term average of the lakes is about 50 percent, according to George Leshkevich, a scientist with the laboratory which is part of the National Oceanic and Atmospheric Administration.

Of all of the lakes, Lake Michigan currently has the smallest amount of ice - about 38 percent. But Lake Erie is almost entirely covered. Leshkevich says Erie often gets the most ice because it is the shallowest of the Great Lakes.

To the north, 57 percent of Lake Superior is covered with ice. As the deepest of the Great Lakes, Leshkevich said, Lake Superior takes more sustained cold air to freeze, and because it produces considerable wave action from prevailing westerly winds, ice is slower to form.

With record low water levels on Lake Michigan and Lake Erie, the massive amount of ice could have a beneficial effect by slowing evaporation from the lake, but other factors could limit the effect.

Last February, the U.S. Army Corps of Engineers reported that Lake Michigan and Lake Erie hit their lowest recorded levels. Last summer, the Milwaukee Journal Sentinel reported on 14 years of below-average water levels on the lakes.

But the relationship between ice cover, evaporation and is complex.

Researcher Jay Austin of the University of Minnesota-Duluth says that the ice "acts like a giant piece of plastic" over the lake. That means water can't evaporate as readily from sunlight.

Austin says that this season's cold weather in late fall and early winter, combined with the relatively warmer water, creates conditions that are "tremendously evaporative."

"Lake smoke" in cities like Milwaukee and Duluth can often be seen rising from the lake. That's evaporation, Austin says.

"So to get to all of this ice, there had to be a lot of evaporation in the first place," Austin said.

In his research, Austin has found that in years of extensive has meant that lakes take much longer to warm the next summer. That could mean cooler lake side temperatures in the spring and summer of 2014

Satellite maps show northern Lake Superior socked in with ice.

On Isle Royale, as late as last Thursday, wolf researcher Rolf Peterson of Michigan Tech said by email that he could still see gaps in the ice and it was premature to say a bridge had formed.

Biologists hope that will happen - the last time was 2008. If ice from Ontario stretches to the island, it could mean the introduction of new wolves, which could help boost the population and diversify the gene pool.

The last time a wolf migrated across the ice was 1997.

The wolf population on the island dropped from 16 in 2011 to eight in 2013.

In their post from the island on Jan. 12, researchers from Michigan Tech tracking the wolf and moose population on the island wrote:

"If climate projections are accurate, only one or two more ice bridges are likely before the is expected to be perpetually free of any significant ice formation (by 2040).

"Ice bridges are important because they represent the possibility that a wolf can migrate from Canada and infuse the population with new genetic material - this appears vital for the population's vitality.'

Explore further: Great Lakes evaporation study dispels misconceptions, need for expanded monitoring program

4.8 /5 (4 votes)
add to favorites email to friend print save as pdf

Related Stories

Lake Erie algae, ice, make a nice mix in winter

Jan 11, 2012

Clarkson University Biology Professor Michael R. Twiss has been working with colleagues and students from Ohio, Pennsylvania, Tennessee and Ontario, to study Lake Erie over the past five winters during mid-winter, ...

Lakes discovered beneath Greenland ice sheet

Nov 27, 2013

The study, published in Geophysical Research Letters, discovered two subglacial lakes 800 metres below the Greenland Ice Sheet. The two lakes are each roughly 8-10 km2, and at one point may have been up to t ...

NASA helps melt secrets of Great Lakes ice

Nov 14, 2013

(Phys.org) —Two scientists from NASA and NOAA have developed a new space-based technique for monitoring the ice cover of the Great Lakes that is so accurate it can identify a narrow channel of open water ...

Recommended for you

Beijing's focus on coal lost in haze of smog

4 hours ago

The soaring, grimy chimneys of the coal-fired power station have belched the last of their choking fumes into Beijing's air, authorities say—but experts doubt the plan will ease the capital's smog.

Stopping the leaks

22 hours ago

When a big old cast-iron water main blows, it certainly makes for a spectacular media event.

User comments : 0