I understand their logic. Sustained temperatures of -30 C (20 below Fahrenheit) must create thicker ice on the lakes than warmer temperatures and thicker ice must take longer to melt than thin ice. It sounds reasonable and if winter temperature was the only factor in creating ice then it would be true.
But there are actually many other factors as well. One of the most important of these is snow depth.
Snow is an excellent insulator. Up here the snow largely doesn't melt until spring. If we get a heavy snowfall early in the winter, it prevents the bitter cold from freezing the lake surface deeply. It insulates the ground as well. Many times in the coldest temperatures you can dig down through three feet of snow and find the ground is unfrozen entirely. There are even some plants growing under there.
Northwestern Ontario has in fact a good quantity of snow on the ground, at least two feet in most places and probably three feet in others.
There's so much snow on the lakes that I haven't been able to use my kick-sled to go ice fishing for the first time since I got it eight years ago. If you don't know what a kick sled is it looks like a lightweight dogsled with runners that protrude behind. You stand on one runner and push with the other leg. With almost no effort you can travel two or three times as fast as you can walk.
Usually the snow on the lake ice is packed down by wind or blown clean off and I can travel easily to my ice fishing spots. This year there's just too much snow and my sled simply plummets through.
I would say the ice thickness near our home here in Nolalu is only two feet. That's about a foot less than normal for this time of year. So there's actually less ice, not more, this winter.
The kind of ice also plays a factor in ice-out. Pure blue ice will absorb the spring sun's rays better and melt faster than reflective white slush ice. So far, this year's ice is almost perfectly blue.
But ice conditions are not the most important predictor of spring ice-out anyway.
The most important factor is spring weather. The weather from mid-March to late-April will determine when the ice will go off Northern Ontario lakes.
What's needed for early ice-outs are temperatures above freezing, lots of sunshine and some warm, rainy days.
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