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Austin Seback /San Juan Expeditions
Opinion vs. Decision
Opinion vs. Decision
Digging snow profiles is a targeted inquiry to measure our assumptions upon which our terrain use is planned. It is not a decision-making tool in and of itself. Digging is part of an understanding and a confirmation of the avalanche advisory. It also helps you to track the seasonal snowpack and associated trends. Data from one observation can help inform an opinion or reduce uncertainty, but a decision involves many more variables that the group should consider. Decisions are also informed by the group's ability, skills, in addition to the conditions at hand.
Dig in the snow to validate and verify expert opinion, not to validate a decision you may be predisposed to. A decision takes into account a seasonal history of the snow, not one data point on a given day. It is important to embrace the uncertainty associated with snowpack on a range scale. One data point, or even many data points may not be enough to quantify the stability of a given slope.
Questions to ask yourself:
Questions to ask yourself:
How repeatable is your data?
How relevant is your data?
How is your craftsmanship?
Are your results biased?
How have you managed spatial variability?
Build your experience by verifying expert opinion
Build your experience by verifying expert opinion
Snowpack tests are another way to validate the advisory and develop your own opinions and understanding about conditions in a repeatable and controlled way. Your opinion based on experience are cultivated over a lifetime in the backcountry. Reliable, relevant results come with mileage and experience in seeking out layers of concern and verifying your opinions and initial assessments with evidence.
Forecasters spend every day in the field and also sort through public input in order to create daily forecasts. So it is important to remember that verifying these opinions should be first and foremost on our minds when we are digging in the snow. Don't dig without a reason, and with out an initial opinion formed by an expert.
Tino Villanueava
Locate layers of concern
Locate layers of concern
Gathering more information can help reduce uncertainty, which can help with making decision about the validity of your plans and where you will ride (as opposed to if you will ride a specific line). Gathering more information about the snowpack generally begins with physically identifying the layer of concern previously identified in the snowpack. Layers of concern are the focus of snowpack testing. You are trying to formulate an opinion on the strength, character and the propensity for propagation on these layers.
Layers of concern or LOCs (as some forecasts refer to them) are the primary driver of avalanche instability. This is especially the case during times of persistent instability. It is important to remember that just because you didn't find the LOC in one area doesn't mean it cannot live just upslope or across slope from the area that you dug. Locating LOCs takes time and practice.
Many professionals have a spatial understanding of a slope and a targeted observation before even walking out the door in the morning. Then, before putting a shovel blade into the snow they will walk around with a probe, testing for spatial variability within the height of snow, LOC, and potential ground cover like rocks and bushes. Only when they have found an area they believe is representative to the LOC, will they dig and attempt to prove or disprove their opinion of the snowpack stability.
This practice takes time to develop an eye, and more importantly a feel for the appropriate areas to dig. Even then, professionals buffer for spatial variability as many terrain features and metamorphic processes are unevenly distributed throughout a slope.
Develop tools that may help reduce uncertainty
Develop tools that may help reduce uncertainty
Physically digging in the snow is the best and most concrete way to increase your understanding of and experience with the makeup of the snowpack. It helps you to connect how weather and time form and change the snowpack. It helps you track how the snowpack changes over time.
Snowpack testing is potentially very dangerous when misapplied, but it's also crucial to have an informed decrease in uncertainty when conditions are changing or without an advisory to summarize current conditions.
Develop your own message about the limitations associated with the use of snow profiles, including craftsmanship, interpretation, replication. Know that a false sense of security due to poorly crafted snow observations, poor site selection, and poor interpretation of results can create a biased opinion which could lead to poor decision making.
These tools are there to help verify expert opinion, or reduce uncertainty in an area without a forecast. They are not there to banish all of the uncertainty associated with backcountry snowpacks. We do not have x-ray vision and thus we will only be able to formulate educated opinions, but we can never be 100% certain.
If the snowpack is the question, terrain is the answer.
If the snowpack is the question, terrain is the answer.
- Drew Hardesty, Utah Avalanche Center
Limitations of digging
Limitations of digging
Digging snow profiles is a lifelong learning undertaking, NOT a decision making tool.
Ensure proper site selection, away from harm but representative of the slope in question
Target your observations, generally around the layer of concern
Slow down and ensure good craftsmanship for repeatable results
Always seek to verify an expert opinion
Interpret your results to form an opinion, not make a decision
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