I’ve been thinking a lot about human factors during considerable avalanche hazard.  There is a reason most accidents occur during this hazard rating: considerable hazard can be hidden from view and it is insidious.

As most people are aware, the snowpack in the South Coast Range is currently in a classic considerable hazard scenario: low-probability and high-consequence. The mid February crust facet layer has created a wide spread persistent slab issue, which has resulted in two recent avalanche fatalities in BC and a full burial on the North Shore.

When a tricky avalanche problem is even surprising professionals, I get concerned for the safety of recreational ski tourers out there making their own decisions about what slopes to ski. This article is not about passing judgement upon any recreational backcountry skier or riders choice of lines. It’s simply to share my perspective on risk management during these types of conditions and hope you can take something from it.

I work full time as a professional guide for backcountry ski touring and helicopter skiing. My job as a ski guide is to provide the absolute best possible ski experience given the current conditions within an acceptable margin of safety. Part of that margin includes stacking the deck so the odds are in my favor.

Last week, my company BC Ski Guides taught our Advanced Winter Travel skills course for a group of North Shore Rescue team members. This is an intensive course designed to take the knowledge of experienced SAR members to the next level. We were operating in the Whistler and Duffey lake areas, where our snowpack tests showed poor results on the mid-feb layer. However, we saw no natural avalanche activity on this layer.  Spooky conditions indeed.  Conservative terrain selection choices were critical to staying safe. We saw recreational parties skiing all sorts of high consequence terrain and getting away with it. Were we just being overly cautious? I don’t think so and I’m fine with my decision.

My concern is for those who chose to ski high consequence terrain and had no avalanche result. They now have a “negative feedback event” stored in their brain:  Given the current avalanche hazard, they chose to ski a particular slope and nothing happened. It then gets filed away in the brain as the correct decision.  Our brains are high performance pattern matching machines, and when presented a similar choice in the future that matches that pattern, we may automatically apply a solution based on past results without even thinking about it.  Unfortunately, the next time a similar pattern occurs, the same decision could have a catastrophic life changing result.

That is why the learning curve for safe travel in avalanche terrain is known as a “wicked learning environment”.  It’s rare you get feedback from the mountains, and when you do, it can be brutal.  The only way to learn is through mentors or peers, which not everyone has the luxury of having.

We must also be wary of our mind playing tricks on us, by substituting a complex question like “is this slope safe to ski?” with a simpler one such as “do I want to ski this slope?”.

These are two of the major themes in Bruce Kay’s excellent book “Autonomy, Mastery and Purpose in the Avalanche Patch”.  I highly recommend reading this book.

The reality is that when conditions are tricky, one will eventually lose the game if the odds are not stacked in your favor. One of those things I stack in my favor is: terrain usage.  If you are going to be out there in considerable hazard, terrain usage is the only thing you can control. Attempting to forecast avalanche stability to justify your desire to ski complex terrain is the wrong approach. There is simply too much spatial variability and our stability testing tools are crude instruments.  Conservative terrain usage is king: lower angle, supported slopes, smaller features, low consequence, etc.  If you don’t know what these terms mean, then it’s time to take an avalanche course or hire a ACMG certified guide. Your life could well depend on it.

For myself and my guests, conservative terrain selection during times of considerable hazard is one of the things that I stack my deck with. I still find awesome skiing and we have fun, which is the real reason were out there anyway.

I hope the rest of your season is a safe one.  Start storing good decisions in your brain!

Tristen Rasmussen
Lead Guide – BC Ski Guides
NSR Avalanche Technician