How The Ice Melts On Leech Lake

I would like to thank Ron Geppert, Secretary of the Ottertail Peninsula Township Association, for developing and/or borrowing the content of this post.
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As we anxiously await soft water again, here are some numbers to digest. The area of Leech Lake is approximately 161 square miles and ice thickness on the lake is about 32". Using basic math, this equates to almost 12 billion cubic feet of ice to be melted. One cubic foot of ice weighs about 56 pounds and one pound of ice requires 144 BTU of heat to melt. Therefore, for ice-out, a total of about 96 trillion BTUs of heat will be required to melt all of the ice, and may take awhile. To understand the process of lake ice melting, here is a quick explanation.

1. In the late fall, the lake loses heat to the atmosphere, and then on a day or night when the wind is not blowing, ice forms. The ice gets thicker as long as the lake can continue to lose heat.
2. In most Januaries and Februaries, snow both reflects sunlight and insulates the lake. With a thick snow layer, the lake neither gains nor loses heat. The bottom sediment is actually heating the lake water slightly over the winter, from stored summer heat.
3. Around March, as the air warms and the sun gets more intense, the snow melts, allowing light to penetrate the ice. Because the ice acts like the glass in a greenhouse, the water beneath it begins to warm, and the ice begins to melt FROM THE BOTTOM.
4. When the ice thickness erodes to between 4 and 12 inches, it transforms into long vertical crystals called "candles." These conduct light even better, so the ice starts to look black, because it is not reflecting much sunlight.
5. Warming continues because the light energy is being transferred to the water below the ice. "Meltwater" fills in between the crystals, which begin breaking apart. The surface appears grayish as the ice reflects a bit more light than before.
6. The wind comes up, and breaks the surface apart. The candles will often be blown to one side of the lake, making a tinkling sound as they knock against one another, and piling up on the shore. In hours, or on a lake the size of Leech Lake days, a sparkling blue lake, once again!

 

Walleye Opener for 2013 in Minnesota is May 11. At last report, just a few days ago, there was still roughly 30 inches of ice on Leech Lake. Given the time it will take to melt the vast sheet of ice currently covering the lake, there may not be open water for this year's Op'ner.