Bottoms up: The lake unveiled

Has the ice gone out on your lake? Were you there to observe it? I had always wanted to see the thaw happen, and this year, at last, I did. It wasn't (as I expected) a matter of observing slow changes over a number of days. In fact, it was sudden, much of the process unfolding in little more than an hour.

Did you know (I didn't until I recently did some reading) that your lake ice thaws from the bottom up? First the snow melts off the surface. Then the sun penetrates the ice and warms the water underneath. Warm air above the ice accelerates the thaw, of course, but it's the warming water below that really does the trick.

When we arrived here on Sunday, April 28, Birch Lake (southeast of Minocqua) was still frozen stiff. That day and the next two days were in the 70s to 80s. Then came three more days of below-freezing temperatures, rain, snow and sleet, before winter's grip finally broke, on Saturday, May 4. At that point, the lake ice still looked solid (we heard reports from other lakes of remaining ice up to two feet thick). Who knew how long it would be until our lake opened up?

Then Saturday saw highs in the 70s, as did Sunday, and Monday, the day it finally happened. I suspect that on those warm-to-hot last days of April, the ice clear of snow, the sun had pumped enough calories into the water to keep the bottom-up thaw going, even as winter came back for a spell.

When I visited the lake's shore Monday morning, ice still covered all except a small area on the far north side. There had been little change (that one could see) when I left for town about 2 p.m. But when I returned at about 5 p.m., about 40 percent of our lobe of the lake had cleared, the remaining ice forming an irregular pattern, like continents in an ocean.

Then, at about 6 p.m., a wind brewed up from the east and began pushing the ice away, at more than glacial speed. Sitting on our deck, I could mark with my eye a feature on an ice sheet, note its distance from the trunk of a tree, and verify its progress. It was a bit like watching the minute hand on a clock, the motion barely perceptible, yet unmistakable.

Within about an hour, all the ice had blown off to the west, the stirring action of wind-driven wavelets surely speeding up the thaw at the same time. Just like that, our entire end of the lake, some 90-or-so acres of it, lay fully open. By morning, the entire lake had cleared, and loons plied the water, crying out with joy.

After the longest winter or the worst spring I remember in my 60 years, a new season has arrived. And all I can say to that is: Bottoms up!