Tuesday, February 22, 2011

Terrain Choices

I spend about 80 days a year backcountry skiing - not slack-country skiing, not resort skiing, all 80 plus days are spent solely in the backcountry, almost all of it in infrequently traveled areas where relying on skier compaction of problem layers in the snowpack is just not an (viable) option. I figure that exposure alone increases the likelihood of being caught in an avalanche, and, truthfully, I've triggered more avalanches than I care (or can) count. So far, I've been lucky and avoided any serious injury - and obviously death - but it means that now, after 20 years of playing this game, I don't look at a single slope without thinking "what will happen if this slides?" As a corollary to that thought, the next thing I think is "can I avoid this slope or minimize my exposure?"

Don't get me wrong, I ski slide paths all the time. As we all know, slide paths make great skiing - angles over 30 degrees and frequently denuded of timber, but, it's one thing to ski down a slide path, and quite another to build an uptrack through the belly of one. There are all kinds of measures you can take to decrease your risk when skiing down a slide path - the most obvious being to expose one person at a time - while switchbacking up a slide path almost inevitably exposes multiple (slow moving) people at a time. Try skiing out of a slide with your skins on - ain't gonna happen.

On a recent ski tour to a local summit, I skied the entire route exposing myself to only one very small area of avalanche terrain - everything else I easily avoided. The rest of my party increased their exposure radically. In the first instance, switchbacking up directly under a slide path that had the sun beating on it with everyone on the slope at the same time, and, in the second, choosing to descend a steep, thin, rocky, shady slope. Neither of these options were necessary, and neither increased the value of the tour - certainly not enough to risk losing your life for. A day later, ski touring in a slightly different area, I came upon an uptrack that switchbacked up a narrow tight gully with big overhead hazard. A classic terrain trap that now had about 15 switchback turns in it. Two hundred metres to the north, was wide, low angle, timbered slope that provided a completely safe route to the same destination.

The key points are undoubtedly clear - look up when breaking trail. If you are directly in a slide path, even a small one, and you can easily avoid it, do so. Do so especially when the sun is beating on the start zone up above you or the wind is rapidly loading it. Do so, even if avoiding it takes a little extra time. Secondly, if you want to ski some nice powder on a shady slope, don't descend where the snowpack is thin and rocky - this is the classic location for triggering slabs on basal facets. Choose instead to descend where the snowpack is fat and healthy. Thirdly, look at the map, look at the terrain, then make a considered decision on where your uptrack should go. The shape and tightness of the contours will tell you where you can find a safe location for an uptrack.

For more tips on managing terrain, read this article by Karl Klassen. Is it a coincidence that we think alike?

 Skier Accidental triggered from an uptrack at the head of Lost Creek

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