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Northland Nature: Snowpack in the March woods

The snowpack in the woods is usually the greatest for the whole season. Here it is on a March day. Note the sunlight penetrating and the slight melting at the base of many trees, "tree circles." Photo by Larry Weber

For many years, March was considered the month of the most snowfall. Though modern weather statistics say that this accomplishment now belongs to January, we still get plenty happening as we go through this month. Early March 2007 gave us a "good old-fashioned" blizzard of nearly twenty inches with wind and drifts.

But a mere three years later, March 2010 came and went with no snow and the snowpack that we had melted. I paddled on the lake by the end of this early spring month. Perhaps we are more inclined to remember the extremes which are impressive, but "normal" March itself is quite impressive.

March may not be the month that we will get the most snow falling on us, but it is the time when normally have the largest amount of snow on the ground. (Note the exceptions of April 2013 and 2014.) This snow cover on the ground is known as the snowpack.

Anyone venturing off the trails or roads to walk in the woods at this time is very aware of the thickness found here. The total amount of snow that has fallen in the last 100 or more days has added up. We also see some "hot spots" at this time; on south or west-facing sites, where much or all of the snow has melted.

Here is where we see early grass greening and maybe the first dandelions in bloom. And there are other changes as seen in the trees. At the base of many trees are "tree circles" where the snow has melted thanks to the dark bark of the trunk absorbing sunlight and reradiating it out into the surrounding snow. To me, this is also a sign that it may be time to tap maple trees.

Warming days followed by freezing nights makes for a crusty snow cover and I find that this March snow may be the best time for snowshoeing. If this coating is strong enough, it can also serve as a terrific time for doing some true cross-country skiing, being able to go anywhere over the snow — not just on trails.

A snow covering the ground for the whole winter is very healthy for some of the local wildlife. Mice, voles and shrews will all go under this blanket and live in a fairly sheltered and protected site in the subnivean space. Rabbits, hare and grouse use this as their shelter as well and remain for days of safe covering; though a bit hungry.

Beneath the snow and adjacent leaves and soil, myriads of hibernating and dormant critters pass the winter. Whether they are chipmunks, frogs, salamanders, snakes or insects, they survive with an ample snowpack.

But this ends with the spring. Longer days and plenty of sunlight sends some news to the forest floor of the impending thaw. This is the beginning of the biggest impact of the March snowpack.

Slowly at first, then quicker, snow will melt and as we pass through the month and into April, the snowpack degrades to very little on the ground. The resulting water goes to the lowest places to form small and often temporary vernal ponds.

In these wetlands, many amphibians and insects will breed in the new season. A thick snowpack at this time in March is a source of water needed for their early lives. Seeing sunlight on the snowpack of a March woods, I find as a good sign of what will happen in the impending spring.

Larry Weber

Retired teacher Larry Weber, a Barnum resident, is the author of several books, including “Butterflies of the North Woods,” “Spiders of the North Woods,” “Webwood” and “In a Patch of Goldenrods.” Contact him c/o Katie Rohman at krohman@duluthnews.com. 

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