- Date
- Friday, January 20, 2017
I recently had the opportunity to run a backcountry workshop for a group of enthusiastic riders in the Yukon, looking to bolster their snow study and observation skills. The Yukon’s Hot Zone Report pilot project is new this year and relies mainly on public observations submitted through the Mountain Information Network (MIN). The group’s goal for the day was to develop their abilities to make more detailed snowpack, weather and avalanche observations to feed the MIN and help build Hot Zone Reports.
A significant portion of the day was spent refining “quick and dirty” snow sense and evaluation techniques, and calibrating these findings as the group felt, poked, and pulled information out of the snowpack with their skis, poles and hands. We also pulled out shovels and got to work examining some of the critical avalanche layers. Snow pits allow us to see what is underneath our skis or sled. They can be incredibly informative but also challenging to interpret. So after identifying and testing some critical weak layers the inevitable question was asked: “So Eirik, what does this mean?”
When I was first introduced to the black art of snow pit analysis I wanted to use the tests I had been shown as a tool to help me decide if a particular slope was safe or not. I was in the habit of digging a hole close to where I planned on riding, whacking on a column of snow with my shovel until something happened, then shrugging my shoulders, unsure of what it all meant. Often I would continue on, regardless of my results.
Looking back, I sometimes consider myself lucky to have made it through those early years unscathed. A snow pit, after all, only gives you very specific information for a particular location. However, as experienced riders know, the snowpack can change dramatically between elevation bands, aspects or even slope features. In using these tests as a “go/no go” tool, I was relying heavily on the assumption that where I was digging was representative of where I was planning on riding. After a couple of close calls, I started looking for more reliable decision-making strategies to manage my avalanche risk.
These days I try to approach my backcountry riding with a more inquisitive mind. I’m constantly seeking out information about conditions that allow me to refine my knowledge of the layers in the snowpack and how they may change over terrain. I feel exposed when I don’t know what’s buried underneath my feet. However, these days, with the wealth of information available online, I often have a pretty good idea of what to expect before I even leave home.
When I’m confident in my knowledge base, it’s often enough to confirm and refine my expectations by gathering information as I’m travelling. I stay alert to changes in the difficulty of the trail breaking, and I’m constantly poking at the snow with my ski pole or probe to explore for weak layers. I also look for obvious clues of snow instability such as shooting cracks or whumpfing, and I am always scanning the terrain around me for evidence of recent avalanches. In fact, many days I might never pull my shovel out of my pack.
At other times, when conditions are unusual, unexpected or unknown, a more thorough investigation is warranted and the most appropriate course of action is to get out the shovel and dig. Sometimes I dig to get a baseline picture of the snowpack, which I can use to build on those quick and dirty techniques I employ as I travel. Other times I might dig to answer a specific question. Can I find that layer of buried surface hoar in a specific type of terrain? How reactive today is the buried weakness that was a concern last week?
Of course, whenever you dig, you’re still faced with the same limitation—the location you’re in might not be representative of other places. If I’m trying to figure out the distribution of a buried weak layer, I’m going to have to dig lots of holes in different locations to try and hone in on the sort of terrain where it can be found. Once I know generally where it is, the next step is digging many more holes over time to track how its reactivity changes. One profile alone isn’t going to give me great answers, but a collection of observations over time will start to reveal trends that are more meaningful.
If that sounds like a lot of work, you’re right. It can be and if you’re going at it alone it could be an impossible task, especially if your skiing is constrained to weekends only. Fortunately, this is where the MIN has huge potential. Sharing our observations when we dig allows us to more rapidly build up a picture of how potential avalanche layers are distributed over terrain, and how they might be evolving over time.
So how do snow pits help us avoid avalanches? Well, they help us identify potential problems. And, as the old guide’s adage goes, “If the snowpack is the problem, then terrain is the solution.” Avalanche risk can be managed by choosing terrain that is appropriate to the conditions.
If I have high confidence in my assessment of avalanche conditions, then I can choose safe terrain based on the expected type and distribution of avalanche problems. For example, I will choose lower angled terrain and avoid slope convexities during or shortly after a period of intense snowfall when storm slab avalanches are more likely. Alternatively, I may choose larger more planar slopes over convoluted features when the hazard posed by a deep persistent weak layer is a concern.
However, I can also use terrain choices to manage my risk when I’m unsure about what, or how much of a problem the snowpack poses. If I’m heading into an unfamiliar area or I expect avalanche conditions could have changed significantly since I was last out, I hedge my bets by choosing benign terrain for my initial foray; the key is to choose a safe place from which to begin the process of assessing conditions. As my knowledge grows, so too does my confidence, allowing me to expand the terrain I feel comfortable in. It can be a slow process at times but one that we can safely accelerate by utilizing the MIN and sharing the observations we make whenever we are out in the hills with others.