What the Lack of Great Lakes Ice Coverage Means

To call it a mild winter would be putting it, well, mildly.

As our current mid-winter warmup rolls on, those in the upper Midwest are either rejoicing at the unseasonable temperatures or are dreading the impact that it will have on the outdoor industries—namely skiing, sledding and snowmobiling. But what effect, we should wonder, will it have on Michigan’s most precious natural resource: the freshwater of the Great Lakes.

To date, the ice coverage on the Great Lakes is only eight percent, according to MLive. One year ago that figure was up at 23 percent, and two years ago at 80 percent. The record for least ice coverage on the Great Lakes since the scientific monitoring began in 1973 is 9.5 percent (2002).

Virtually all of the ice coverage that exists currently resides in various bays, such as Little Traverse Bay, Black Bay and Green Bay, with a little in the Straits of Mackinac area as well. A historical view of ice coverage on the Great Lakes is available here.

According to the Great Lakes Environmental Research Laboratory, “ice coverage on the Great Lakes plays an important role in determining climate patterns, lake water levels, water movement patterns, water temperature structure, and spring plankton blooms.” Prior to this winter, the GLERL’s climatologists predicted, using two different models, that the ice coverage in 2017 would fall between 44 and 64 percent. As of right now, we’re not even close.

img_1385On the surface, it appears there can be both positive and negative effects for low ice coverage. For one, fish that spawn in the shallow waters, which are more commonly covered in ice, rely on the coverage to protect their eggs. However, when there is little ice coverage, more light is able to find its way through the water to support algae growth, which helps “support living organisms in the lakes.”

Along the shores of the Great Lakes, ice can serve as both a platform for fishing as well as a stability structure to limit the amount of erosion that occurs. When that ice is missing, not only are the shorelines more vulnerable to being eroded, but the rivers and streams can increase past typical pressures for wintertime.

During mild winters when Great Lakes ice coverage is low, there is nothing limiting the amount of water that evaporates, thus contributing to lower water levels on the lakes heading into spring and summer. Great Lakes water levels have been a constant area of concern over the last several years.

Looking ahead, after a hot summer in 2016 that left the Great Lakes at very warm temperatures heading into the winter, the lakes will now have a jump on warming into the summer 2017 months. This head start could ultimately give the lakes an advantage at increasing evaporation in the upcoming summer and fall, thus creating lower water levels in the year to come, rather than immediately. Water levels and temperatures can have an effect on many things, such as the health and reproduction of fish and other species, the fishing industry, the patterns of currents, and the shipping industry.

The long-term effects of the shift in ice coverage is currently being widely-researched and is still up for debate about any permanent changes that may occur. But here in Michigan, what’s important is that the Great Lakes are our most valuable resource. Let’s treat them that way.






  1. Reblogged this on Midwestern Plants and commented:
    Us Midwestern folk are enjoying a mild winter so far. I don’t know of anyone that is complaining… well maybe the snowmobilers, skiers and snowman builders are. ☃
    I thought this post was an interesting read about how this warm weather is effecting the Great Lakes. Please go read the full post at upnorthreader.com!


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