The Strange
Once the snow piles up in our woods and we finally get all the trails packed, groomed and set, strange things happen out there.
It seems like things are pretty normal and stable until there’s around 18” of snow on the ground. At 18” of snowpack, we’ve only got about 6” of packed base on the trail, so there is a 12” difference in height from the trail to the top of the snow column. That’s when things begin to happen.
Now, we’ve got to think in slow motion while we talk about these mid-winter occurrences, these actions take days, sometimes weeks to develop and reveal themselves. They happen every year, even on a low-snow year like the one we’ve had. They’re awesome, frustrating and always a certain kind of magic.
The snow-pack acts exactly like a fluid once it reaches a certain depth. Right, a fluid. It spends the whole rest of the winter trying to level out, find the lowest point. While it’s busy seeking its lowest point, it’s pulling all that 3’, 5’ and 7’ brush down towards the trail with it.
It’s frustrating after the club has spent hours cutting brush all fall to watch the taller seedlings bend down toward, and then onto the trail. We always say we’ll cut further away from the center line next year; but we never do.
Watch the snow on all these metal roofs, especially unheated buildings. The snow slowly creeps down the roof and then curls into nothing more than a breaking wave. Waves. An object passing through or on a fluid creates certain types of waves. Next time you are in a moving motorized boat, look back. The boat is creating two types of waves, depending on its speed. There’s a standing wave and a shock wave (if the boat is gong fast enough). Thinking in slow motion, the same thing happens on our trails. Our ski trails don’t have the problem the snowmobile trails have. Next time you are on a snowmobile trail, especially like on a Saturday afternoon or a Sunday evening, notice the rollers, or bumps or ‘moguls’ (as snowmobilers call them). They’re always there, a certain height (amplitude) and a certain distance (frequency) apart. The snowmobiles, moving through a fluid (the snow on the trail) have created standing waves. If we could find a snowmobile and a driver (I know a few, some are deceased) that could go fast enough through unpacked snow, the machine would create a standing wave and a shock wave much like a speed boat. I said our ski trails don’t have the same problem; but there are years where we’ve noticed a standing wave develop on the Montreal Trails ‘Grade’. It’s a subtle, low, stretched out roller that’s about 12’ from crest to crest. We hardly notice it while skiing.
That’s the fluid magic that goes on out there all winter. It’s fun to watch if you’re a snow geek like me and have hundreds of hours inside your head driving a machine running a monotonous 4200rpm each season. Or, maybe it’s the fumes, I don’t know.
I’ll quit on the magic we see in our snow for now. Perhaps I’ll write about other exciting things like destructive metamorphism, or depth hoar. I may feel like describing area release and shear zones: all snow situations we have in the Midwest. I’ll stay out of the things that happen in the mountains and I won’t begin to describe some other things that go on. I just don’t have the projetives or the adnouns to try to make you possibly, maybe, perhaps - believe me.
We live among miracles. I hope you ever get too old or too calloused to never be able to appreciate them. Ski Freely. Z
