Ice Reflections, or Not?

January 19, 2013 Comments Off on Ice Reflections, or Not?

Jan. 19, 2013

Ice, ice, ice. Here in northern Minnesota we look for ice on lakes and ponds, and want it nice and thick. But last week, we got a much more southern version of ice in the form of the second significant rain event in less than a month. I’m not a fan of that kind of ice, but it does give you lots time to think as you chip away at the layers.

Friday, I tackled the sidewalk between the house and the garage out of sheer necessity and a desire to be able to remain upright walking out there. It was still misting while I was doing it and I also knew that it was going to cool down and get much more difficult to deal with after Saturday, so choices mostly removed, I went to work. During the time I was chipping, I got the first audible sign of spring- Black-capped Chickadees singing their spring song fee-bee. At first thought it seemed a little disconnected, but further thought said “hey, it is almost 40 degrees out here, of course they think its spring!” Actually I knew this at least was not really an unusual event, more like a bit of normal in the otherwise not so normal event of rain in January. I always love to hear the optimistic Chickadees in the middle of winter!

Saturday, I went to Sugarloaf, and arrived by mid-day so I had plenty time to deal with whatever awaited me there ahead of the scheduled star program that evening. As it turned out, I did some ice shoveling there, but there it was more like shoveling really heavy slush. Thankfully the north shore didn’t get the ice that we did inland in Duluth. However, there was enough water running down the driveway to produce the normal water pathway past the building down the trail to the lake. This is more of a non-winter phenomenon at Sugarloaf, but there it was. While there, I took a trip down to the beach to see what there was for lake ice in the cove. What I saw was nothing more than a very small amount of icy splash on the shore.

This got me thinking about how the ice patterns on Lake Superior and the Great Lakes as a whole are changing in a big way. In the past 40 years the amount of lake ice in the winter for all of the Great Lakes has decreased 71% according to a report by the American Meteorological Society in February 2012. This information was gained from ice coverage reports from the Coast Guard as well as satellite images over 40 years. Ice coverage on Lake Superior has decreased 79%, and reflects the trend that Lake Superior is feeling the effect of climate change in a more drastic fashion than the surrounding land.

How does the change in ice cover impact the lake? Well, it turns out that it affects a number of things. First of all, during the winter lake ice reflects light and keeps the amount of evaporation of water from the lake down through the winter under normal conditions. Little or no ice, more evaporation occurs, which can lead to lower water levels. Less ice also means that the lake temperature begins to warm sooner. Dr. Jay Austin and researchers at the Great Lakes Observatory in Duluth have found very direct links between the amount of ice on the lake and the dates when the lake begins to form a warmer layer on the surface. This is called stratification, and usually doesn’t really begin until July, but with little ice cover this becomes earlier and earlier, in fact the researchers from Great Lakes Observatory have found that this event is happening about a half day earlier every year. That’s a pretty dramatic change in a short period of time. In fact, air temperatures surrounding Lake Superior are increasing half as fast as the water temperatures.

In the winter of 2012, approximately 5% of the Great Lakes froze over, compared to the average of 40% of the lakes froze over. That’s a big change. In fact last year, the ice was so little that sheltered Chequamegon Bay, between Bayfield and Ashland, WI didn’t freeze enough to create the traditional ice road to Madeline Island in the Apostle Islands. This meant the Madeline Island Ferry had to run all winter long- this has only happened once before.

It will be interesting to watch and see what happens to the lake ice on Lake Superior this year, maybe the return this weekend of more normal Minnesota temperatures below zero will help. You can check current ice conditions at a NOAA link (Click here and select Great Lakes Daily from top middle drop down). Currently, there is not much ice on Lake Superior, or any of the other Great Lakes. But maybe some serious cold will help us develop some lake ice and the next trip I make to Sugarloaf Cove will show a bit more exciting developments on the beach. Here’s hoping for more ice!

These updates are made possible by a generous donation from David and Rosemary Good.

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