While those of us in the Northwoods have shivered our way
through December, January and now most of February, a silent war has been
playing out on your lake, and mine, and others.
Below-zero temperatures, day after day, want to make the ice
thicker, while two feet or so of light, fluffy snow wants to act like the Pink
Panther’s favorite product and insulate. So, in the face of this winter’s
record-challenging cold, who is winning? Is the ice steadily building or is the
insulation keeping its thickness close to normal?
It turns out the answer isn’t entirely clear. Today I asked a
young man at Kurt’s Island Sport Shop in Minocqua (Wis.) what ice conditions
are like on the local lakes. He told me that on average the ice is about 30 inches
thick. That’s a lot of ice, but not unprecedented, and as cold as it has been I
wouldn’t have been surprised if it had been much thicker. Last February here on
Birch Lake (near Harshaw) I went ice fishing with a friend, and we had to
power-auger through more than two feel of ice to find water. Of course, last
year wasn’t as cold, but there was very little snow cover.
So this year it seems the snow’s R-value is having an effect. And the snow is having other effects too. The fellow at the sport shop said there’s
a heavy layer of slush beneath the surface snow. Why? According to the folks at WinterTrekking.com, slush forms on top of lake ice from overflowing
water:
"As soon as it snows on top of ice, that creates a force pushing down on the floating ice. All ice, including perfectly safe thick ice, naturally cracks day and night, expanding and contracting with changing air temperatures. When the ice cracks, water can rush up through the cracks on top of the ice but under the insulating snow, and form slush pockets. These slush pockets can become very broad, sometimes covering entire lakes under the snow, and they are a hazard to travelers."
"As soon as it snows on top of ice, that creates a force pushing down on the floating ice. All ice, including perfectly safe thick ice, naturally cracks day and night, expanding and contracting with changing air temperatures. When the ice cracks, water can rush up through the cracks on top of the ice but under the insulating snow, and form slush pockets. These slush pockets can become very broad, sometimes covering entire lakes under the snow, and they are a hazard to travelers."
And what’s the consequence? A lot of ice anglers are getting
their 4-wheelers stuck on the way to their shanties. They’re learning a lesson
from trout fishing writer John Gierach: "Four-wheel drive doesn‘t mean you can
go anywhere. It just means you can get stuck in worse places.” And I can’t
think of many worse places to get stuck than hubcap-deep in slush in the middle
of some lake snowscape. So if you’re going fishing these days, a snowmobile is
the best way to get to your favorite spot (if it’s too far out to reach on
snowshoes).
