Know the Snow: Pushing the envelope

Two weekends ago, my wife and I were skiing with the kids at Eaglecrest Ski Area. One windy trip up Ptarmigan redefined the weather limit of little ones for me. I learned young skiers don’t like strong winds and blowing snow.


They are not alone; the snowpack doesn’t like it either.

Later that day, ski patrollers in the West Bowl started to see clear signs of instability like shooting cracks in front of their skis. A few days later I heard about two close calls that happened that day in the backcountry. The fact that I know of two close calls suggests that there were likely a few more incidents in the back country that day.

And it wasn’t the first weekend with an unstable snowpack.

The question is: What was so special about that Saturday that caused folks to get into trouble?

It is clear why riders wanted to venture into the backcountry under these conditions — the snow was great.

But the snow was also dangerous.

Why do we decide to take our chances for short-lived satisfaction when there is so much at stake?

There are several reasons why.

One reason that may apply to many of us backcountry enthusiasts is what avalanche and decision-making folks refer to as “negative reinforcement.”

Negative reinforcement takes place when we take risks we shouldn’t take and get away with it. In time we tend to believe that our risky behavior is normal and keep pushing the envelope. Little do we realize, the cards are slowly stacking against us and, eventually, the conditions will not be stable and the outcome will not be in our favor.

From my relatively short perspective, the snowpack around Juneau is stable most of the time. True, avalanches are very easy to trigger during, or shortly after, snow and wind events. But these periods of instability are typically short-lived and the snowpack becomes stable within a few hours. The problem starts when, for some reason, this instability lingers for a longer time than usual.

That’s what happened during the weekend of Feb. 22 and 23 locally. After two days of heavy snowfall, Saturday morning was a relatively nice day with light precipitation and partly cloudy skies that gave the illusion that the snowpack was quickly becoming stable. The winds, however, kept moving fresh snow from one slope to another, increasing stability on some slopes and decreasing it on others. For people who are used to going out into the backcountry shortly after a snowfall ends and getting away with it on a regular basis, Saturday, Feb. 22 was just another one of those days. The difference was that the snowpack didn’t care, and it became more and more unstable on lee slopes.

The big challenge when dealing with negative reinforcement is to recognize the problem in the first place. Ski patrollers and other avalanche folks that use explosives to trigger avalanches regularly figure out fairly quickly where they can or cannot push the envelope.

Recreationalists, on the other hand, don’t have the benefit of loading slopes with explosives and seeing what happens under many different conditions.

One way of dealing with negative reinforcement is to rely on the law of large numbers. For instance, all of my friends and I may be getting away with pushing the envelope. But if my friends’ friend and their friends and so on will keep pushing the envelope, eventually someone will trigger an avalanche and get in trouble.

As someone who studies avalanches, I want to know about this person. I want to know what they did to trigger a slide, how they did it when and where.

Indeed, learning from someone else’s experience is not the same as experiencing it yourself, but it’s better than not knowing at all and in the avalanche business, it is also way healthier.

The month of March started with five fatalities in three days. One climber, one snowmobiler and three skiers and snowboarders died in avalanches. The last fatality involved a local Juneau heli-ski and snowboard guide Christian Arcadio Cabanilla. I would like to take this opportunity to send my deep condolences to Cabanilla’s family and friends.

• Ron Simenhois is an avalanche forecaster who lives in North Douglas; contact him at


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