Sarah and Don Carpenter, owners and lead instructors at the American Avalanche Institute, use the Risk Equation when ski touring in the backcountry. In addition, they also use the risk equation when planning a mountain biking or hiking trip.
This blog and accompanying video will review how to use the risk equation, plus why you must also factor in exposure and vulnerability. Once you can properly identify the risks, you then can create a better plan of how you should address them.
What is the Risk Equation for Backcountry Travel
When focusing on determining the risk while ski touring, we’re looking at a graph of the Likelihood versus the Consequences. This is what mother nature provides us, and we do not have control over. However, the risk equation also involves exposure and vulnerability. These two things we can change.
Exposure and Vulnerability
We can limit our exposure, and completely avoid the avalanche problem by not entering avalanche terrain altogether. Furthermore, we can limit our vulnerability by wearing a transceiver, a helmet, an airbag, and being prepared for a rescue situation. But in the end, exposure is a better way to manage the problem by choosing better terrain.
The Risk Equation: A World of Uncertainty
When you think about the likelihood of something happening, you have a range from zero probability, so it will never happen, to 100%, meaning its certain to happen. Whether in the world of backcountry skiing, rock climbing, or mountain biking, we often exist in a middle realm of uncertainty. Meaning the likelihood of something happening while participating in adventure sports is always somewhere in between 0-100%.
Along with this likelihood comes the consequences. What happens if there’s an avalanche here? What happens if I fall off my mountain bike? When speaking about backcountry skiing, the consequences depend on the size of the avalanche and what type of terrain you are in when it happens. The exposure of that terrain could greatly increase the risk of that avalanche problem.
Risk Analysis and Reducing Vulnerability
When we analyze the risk equation, we need to consider vulnerability. As an example: I am much more vulnerable if I’m not wearing a transceiver when an avalanche occurs. So how do we reduce our vulnerability?
Ways to Reduce Your Vulnerability:
- wear a transceiver or beacon, and know how to use it
- wear an airbag, and know how to use it
- wear a helmet
- limit your exposure
Ways to Limit Your Exposure:
One of the best ways to limit your exposure while backcountry touring, skiing, splitboarding, or snowmobiling is by choosing the right terrain. We never want to get caught in an avalanche. But, if we were to get caught, what terrain are we in? What terrain are we near that can help us limit our risk?
Therefore, choosing the right terrain will help limit your exposure, reduce your vulnerability, and the risk of a bad outcome.
How To Choose the Right Terrain
Most avalanches occur within a slope angle of 30-45 degrees. So, if we choose low angle terrain, below 30 degrees, this will be a safe option. How about the terrain surrounding that low angle terrain? Are there steeper slopes above? Is there a gully or cliff band below?
Review your terrain options during your planning phase at home as part of the risk equation. Need help planning? Review our AAI checklist.
Set Your Objective and Reassess
So, set your objective for the day and choose the most appropriate terrain for the conditions and the forecast. Then, once you are in the field, reassess all the factors on an ongoing basis to determine your risk.
Be aware of the likelihood of triggering an avalanche. How big is going to be? What is the exposure based on the terrain I am in? What is below me? Always look at the risk equation and attempt to minimize your risk.
Consequences Related to the Mechanism of Injury
The type of terrain you choose will also determine what type of injuries might occur.
Ex: Say you are on a slope and get avalanched, and below you is a nice, gentle runout. Your exposure, chance of injury and type of injury is lower than if you get avalanched through a steep stand of timber. If you are being dragged through trees, your body would be impacting those trees at a high rate of speed. It would be like trying to jump out of a moving truck and latch onto a telephone pole.
In your planning, think about terrain, slope angle, and escape route in the risk equation. This goes for adventure sports like mountain biking as well.
Reading the Avalanche Forecast and Identifying Risk
During the planning phase, you will also be reviewing the avalanche forecast and factoring this into your risk equation. Avalanche ratings or hazards will fall under one of the following categories:
Keep in mind, a rating of moderate hazard could mean that it’s really unlikely that you will trigger a big avalanche. It could also mean that it’s almost certain you will trigger at a small one.
Therefore, just using the graph of the likelihood versus the consequences is not enough to determine the risk equation. You need to overlay those two factors with vulnerability and exposure each time you plan a backcountry adventure.
Are you interested in further improving your snow safety knowledge and staying sharp for your next backcountry adventure? Check out our current course offerings:
We are proud supporters of the American Avalanche Association. A3 is a 501(c)(3) nonprofit organization dedicated to professional excellence in avalanche safety, education, and research in the United States.