Thoughts, ideas, comments, diatribes, and rambles. A subjective take.

They Just Keep Dying: Why ‘Experienced’ Riders are Dying in Predictable Avalanche Accidents, and What We Can Do About It.

At about 10:15 in the morning on April 20th, 2013, five snowboarders and one skier met in the parking lot of the Loveland Pass ski area for a backcountry tour up the Sheep Creek drainage   They  were participants in the Rocky Mountain High Backcountry Gathering, an event organized to promote backcountry snowboarding and avalanche safety. The participants discussed the plans for the day and began to skin up an old summer road towards low-angle terrain at the other end of the drainage.

Within minutes, having skinned only a few hundred yards, all six members of the party were buried by a slab avalanche measuring 800 x 600 feet, with an average depth of 5 feet, in some places 12 feet deep. One was buried to his neck and survived, trapped for four hours touching two of his buried friends but unable to move.  The other five perished, some buried 10-12 feet deep.

sheep creek avalanche

Sheep Creek Avalanche Site: The group entered the toe of the path from the right, within a few hundred yards of the parking lot. (Photo: CAIC)

The CAIC described a deep slab danger on exactly the aspect in question that day: “If you find the wrong spot, the resulting avalanche will be very large, destructive, and dangerous”, said the forecast that morning .

The CAIC accident evaluation reported, “It is rare that we have as clear of evidence of a deep-persistent avalanche problem as we did the week leading up to this accident. Some of the group likely drove by fresh evidence of the problem in Straight Creek on their way to Saturday’s event. Before their tour, the group read about the conditions in the avalanche bulletin and identified deep-persistent slabs as the primary avalanche problem.”

In an interview with Aspen Public Radio three days later, Ethan Green, director of the Colorado Avalanche Information Center said, “We were describing this sort of situation. And so how could a group that was well prepared, knowledgeable, hopefully had looked at the advisory, still get involved in an avalanche like this?”

The Avalanche Education Glass Ceiling

Summer is just around the corner.  Here in Portland, the days are unseasonably warm.  The wise are pulling out their corn-snow skis, while other are breaking out their rock shoes.  It’s a hard time of year to think seriously about avalanche science.  Nevertheless, earlier this week, the Sheep Creek Avalanche became the deadliest avalanche to ever strike backcountry recreationalists (CAIC report here, excellent WildSnow.com site visit here).  The members of the group were educated and part of a gathering focused on avalanche safety.  Nevertheless, they got themselves killed within minutes of leaving the parking lot.  This begs the question: Why do ‘experienced’ riders continue to die in the backcountry?

This is not the first such episode in which an ‘experienced’ group met tragedy, but merely the latest.  On February 19th, 2012, three skiers died in a slide that caught five off the backside of Steven’s Pass resort, an incident which was the subject of an impressive NY Times piece published earlier this season, Snow Fall: The Avalanche at Tunnel Creek (NWAC report here).  Earlier that same season, on November 13, 2011, professional skier Jamie Pierre was caught and killed in an avalanche within the unopened Snowbird ski resort in Little Cottonwood Canyon, UT.  The danger rating was considerable. Ski patrollers stood at the bottom of Snowbird and Alta ski resorts warning backcountry users that in spite of the blue skies, the snowpack was shallow and dangerous. Pierre and his partner carried no avalanche equipment, and triggered the fatal avalanche after having triggered a large slide that obliterated their boot pack just hours before.  That same day, there were 12 human avalanche involvements within 10 miles, two requiring professional rescue.

Jamie Pierre Avalanche

The avalanche that Jamie Pierre and his partner triggered and ignored before continuing on to trigger the avalanche which claimed Pierre’s life. (Photo: Utah Avalanche Center)


The following week, I sat in a conference room at the National Weather Service, invited for the first time to the Utah Avalanche Center’s (UAC) annual observers meeting. An exasperated Bruce Tremper stood in front of the group to ask “What more could we have done”.  The danger that day was Considerable to High, and the forecast was explicit that it was on “days like these” that accidents happen in the backcountry.

Many ideas were batted around the table.  Much more work goes into even the tiniest details of avalanche forecasting and the spreading of that information than many think.  Bruce Tremper and all of the other wonderful forecasters at the UAC worry daily about how to best keep people safe in the backcountry.  But still people die.  That’s because when it comes down to it, all that can be done is to arm the backcountry population with tools to navigate the snowpack.  It’s up to them to use them well.

Not all hope is lost, however. Though the population of backcountry users is exploding, the annual avalanche fatality trend has not followed that climb since it plateaued around the year 2000 (NWAC). With a growing population of backcountry users, the US experiences about 30 fatalities per year on average. This is an encouraging statistic. Nevertheless, in spite of forecasts, safety equipment, and growing avalanche education, that number isn’t changing much.  This suggests that while avalanche education is keeping us a little bit safe, it isn’t going the whole way, and has struck a glass ceiling when it comes to further reducing fatalities.  Worse, with a bigger population accessing the backcountry every year, some backcountry hazards, namely human factors and heuristics, are likely to become a more prevalent cause of accidents, and without a change, that number of fatalities may again begin to climb. We are at a turning point in backcountry use– whether we can adapt avalanche education to save lives is the question.

Hostile Environments and Heuristics

Becoming educated about avalanches, either by taking an awareness course or a basic avalanche training course, places you at greater risk of dying in an avalanche.  Roughly two-thirds of those involved in avalanche accidents have formal avalanche education, and of those, about two-thirds describe their education as “basic” or “aware” (Tase 1999). These groups, and they are, for the most part, groups, carry avalanche gear, perform stability tests, and generally read the forecast.  So why are there still so many accidents?

The answer is a word which is coming to define avalanche science: heuristics.  Heuristics, in their basic sense, are rules of thumb, or subconscious decision-making schema.  We use heuristics every day to simplify our lives and reduce the decision-making required for simple tasks.  If every time that you drove through a familiar garage or walked to the grocery store you had to construct a strategy for such from scratch, you’d spend much more time and energy going about your day. Thankfully, our front country environment is largely predictable, and so simple rules of thumb can save us time and energy throughout the day.

Common examples of heuristics are as follows:

Familiarity: Things which are more familiar to us are safer.  We can expect a familiar environment or situation to repeatedly be have in a familiar way.

Social Proof: If others are taking part in something, it is likely both a safe thing to do, as well as a desirable thing to do.

Scarcity: Resources which are intrinsically valuable are made even more valuable when scarce.

Experts: We should generally allow experts to make decisions for us in the areas of their expertise.  Increased knowledge of a subject is assumed to lead to a better ability to make decision about that subject.

For better or for worse, the backcountry environment that is the arena of avalanche accidents isn’t one well-described by heuristic rules.  The snowpack, due to spacial variability, represents a ‘hostile’ decision-making environment.  In this environment, it is impossible to know everything about the snowpack, and further, when we make decisions about the snowpack, it doesn’t provide us will clear or immediate feedback.  It is possible for a skier to make unknowingly risky decisions for many years and simply to get lucky.  During this time, however, many skiers will think that they are making good and correct decisions, and their notion of how to travel safely, however flawed, is reinforced by the fact that they don’t end up in an avalanche until the big one that kills them, or almost does.

The implication of a complex and hostile decision-making environment is that while avalanche hazard assessment and rescue skills are certainly necessary for safe travel in the backcountry, they are in and of themselves insufficient to keep us safe. Because our decision-making rules are liable to get us into trouble, it is necessary to develop tools and procedures which attempt to limit or at least make clear the fallible aspects of our decision making.  Avalanches aren’t inherently dangerous– they only become so when we walk into them.  We have to address the human factor.

Human Factors: Codifying Risk, Reducing Error

If we accept that poor human decision-making is the cause of almost every avalanche accident and fatality, and we should, then the question becomes one of limiting the fallibility of our decision-making.  As described above, the hostile decision-making environment of the backcountry snowpack is one to which we are poorly suited– that is, we are not just not good at making good decisions about backcountry risk, but we are congenitally bad at making decisions in such an environment.  The tools that we use to simplify our everyday lives are those which subject us to most hazard.

The clear implication of this human fallibility is a need to codify risk and structure the information that we can gather into an algorithmic decision-making process which checks our decision-making for us. By examining the available snow science and avalanche statistics, it is possible to construct a sort of risk-matrix to guide our decision making in the backcountry.

In Europe, this codification effort has been ongoing for some time, and in the US/Canada it has been slowly adopted since about 2001. Ian McCammon, North-American go-to man for human factors research, has helped to summarize the available research for North America into decision-making frameworks.  Best known among avalanche professionals is the notion of “avalanche lemons” in the snowpack (inherently unstable or energetic characteristics), which when present in sufficient number are statically likely to produce an avalanche (McCammon, 2002, A field method…). This is a strategy which is now employed in AIARE avalanche courses and in AIARE field books for observations.

A still-simpler method exists, also courtesy of McCammon.  This is the use of two Acronyms: ALPTRUTH and FACETS.  The use of these is just as effective as the idea of Avalanche Lemons, if not moreso, and they have the potential to prevent  between 92 and 98% of all accidents


ALPTRUTH tableThe ALPTRUTH system reduces the terrain and weather factors which commonly contribute to accidents into 7 categories which are designed to be easily recognizable.  The idea is that before skiing a slope, or when making travel decisions, it is easily remembered and referred to as a decision-making tool.  Research by McCammon (2004) and Hallandvik et. al. (2012) suggests that in different snowpacks, the ALPTRUTH system has the potential to prevent upwards of 65% of all avalanche incidents, and potentially as much as 98%.

The acronym is easily written on the back of a glove or on a ski pole, and it’s some of the best life-insurance that a backcountry traveler can have. The process is simple: assign one point for each factor present.  92% of accidents have 4 or greater points, 98% have three.  To be very clear, if you simply didn’t go any time that 3 points were present, you would avoid 98% of all avalanche accidents.  It’s a stunning idea, and if we apply it the recent Sheep Creek avalanche, the results are clear, as we can see below:

A: The Colorado avalanche center described in their forecast recent slab avalanches on similar slopes/elevations/aspects within the 24 hrs prior to the accident.

L: The slope is question was heavily wind loaded and continued to load throughout the day.  Even when the avalanche investigation was undertaken, part of the crown had already reloaded.

P:  Not only was the fatal path large and clear, with an absence of mature timber, clearly defined edges, and ideal slope angle, but the party also traveled through an obvious avalanche path to reach the fatal path.

T: The party was travelling immediately uphill of trees at the toe of the path, which became a consequence multiplier during the slide.

R: The avalanche hazard was considerable.  The party discussed the hard slab danger in the parking lot, and so was clearly aware of such.

U: “Some of the group likely drove by fresh evidence of the problem in Straight Creek on their way to Saturday’s event”.  It is unlikely that the group experienced a collapse until the collapse that decimated their party, as they had barely left the parking lot, so we will give it the benefit of the doubt and not assign a point here.

T: None.

What is notable is that five, if not six, of the seven total obvious signs were present and easily evaluated on the day of the accident. This would have quickly assigned a Not Recommended decision to their travel plan. For your own satisfaction, apply this acronym to either the Tunnel Creek or Jamie Pierre fatalities.



Your buddy hit it.  Will you?  Social proof in action.  Photo taken during by 2010 AIARE Level 2 in the Mt Baker backcountry after a witnessed avalanche.

Your buddy hit it. Will you? Social proof in action. Photo taken during by 2010 AIARE Level 2 in the Mt Baker backcountry after a witnessed avalanche.  Notice that the skier skied onto the slope immediately adjacent to a recent avalanche crown.


The snowpack alone is not sufficient to describe the risks in backcountry travel. Thus, McCammon also suggest the use of FACETS, a human-factors acronym:

Familiarity: “Parties traveling in familiar terrain made significantly riskier decisions than parties traveling in unfamiliar terrain. This effect was especially pronounced for parties with substantial experience and training.”

Acceptance (Social): Group members want to be accepted by members of their parties. “Accident parties that included females made riskier decisions than parties of all males. The effect was most pronounced in parties with little avalanche training. It is notable that these were precisely the parties in which women were least likely to participate.”

Consistency/Commitment: “Parties that were highly committed to a goal – a summit, ski slope or an objective in deteriorating weather – made riskier decisions than parties just out for a day of skiing, climbing or sledding. This effect was most pronounced in parties of four or more.”

Expert Halo: “Accident parties often contained a de facto leader – someone who was more experienced, older, or who had better skills. Remarkably, when this leader had poor avalanche skills, novice groups were more likely to follow their leader into dangerous situations than when novice groups made decisions by consensus.”

Tracks/Scarcity: “Parties took more risks when they were racing a closing window of opportunity, such as competing with another group for first tracks.”

Social Proof: “When skilled parties met other people in the backcountry, they were more likely to take risks than parties that were less skilled. This effect, known as social facilitation, was most pronounced in groups with the highest levels of training.”

To my knowledge, this hasn’t been codified into a point-based decision-making structure as has ALPTRUTH.  Nevertheless, write it on your other glove or ski pole, and think of it as a multiplier for FACETS.  The greater the number of potential FACETS points, the more that you need to keep your head on a swivel and be afraid of the potential for poor decision-making.

Next Steps in Avalanche Education

Formal avalanche training did not appear to equip these victims with effective tools for decision-making. If these victims had used the knowledge-based decision strategies that are commonly taught in avalanche courses, we would expect very few accidents under such obvious conditions. Instead, we find that even well-trained victims appeared to ignore easily recognized signs of avalanche hazard. Thus it appears that they were either unwilling or unable to apply what they had learned. Of course, these victims represent a very special group of people: those that were caught in avalanches, and so they may be uniquely prone to poor decisions. But if they were instead typical of many recreationists, their susceptibility to heuristic traps suggests a reevaluation of how courses prepare students for making decisions in avalanche terrain. 

McCammon 2004
From Tremper (1991)

From Tremper (1991)

Modern avalanche education is all about the red flags: what are the obvious signs of instability, and how can we recognize them?  In Level I and II courses, you practice beacon rescue, perform snow pit tests, and squint at little pieces of ice on your crystal card. You come away with an appreciation for the conditions necessary for snow to start sliding down a hill.  Only to a much lesser extent do you appreciate the myriad ways that humans end up in front of that snow.

I think that avalanche education, in its current form, is necessary and valuable.  It is, however, obviously and indisputable insufficient for safe travel in the backcountry.  I learned compression tests from instructors, but what I know about staying safe and traveling in a group, I’ve learned from my mentors.  Human factor education and codified decision-making systems like ALPTRUTH need to be incorporated into avalanche course curricula to a much greater extent.  How this could happen is not difficult to imagine– the human factor hazard simply needs to be given greater weight than the snow science.  Classes can review the numerous well-documented avalanche cases and discuss not only the snowpack which contributed to them but the human factors as well.  By doing so, instructors to trail students to use these decision-checking frameworks before walking blindly into clearly hazardous situations.

If we want to live long and happy lives in the backcountry without learning lessons the hard way, then we need to cement an awareness of human factors into the backcountry culture.  Begin with educating yourself.


Dale Atkins, Human Factors in Avalanche Accidents, 2000.

Fredston, Fessler, and Tremper, The Human Factor – Lessons for Avalanche Education, 1994.

Linda Hallandvik et. al. Could Fatal Avalanche Accidents in Norway from 2005-2012 Been Prevented Using the Reduction Method, the Basic Reduction Method, and the ALPTRUTH method?, 2012.

Ian McCammon, The Role of Training in Recreational Avalanche Accidents in the United States, 2000.

Ian McCammon, Evidence of heuristic traps in recreational avalanche accidents, 2002.

Ian McCammon, A field method for identifying structural weaknesses in the snowpack, 2002.

Ian McCammon, Comparing Avalanche Decision Frameworks Using Accident Data from the United States, 2004.

Jessica Tase, Influences on Backcountry Recreationalists’ Risk of Exposure to Snow Avalanche Hazards, 1999.

Eric Knoff, The Human Factor – The Avalanche Wildcard, 2012.

Bruce Tremper, Life as a Human Being, 1991.

The Avalanche Handbook, 2nd Ed.  McClung, D. and Schaerer, P. 2002. The Mountaineers, Seattle, WA.

Allan & Mike’s Avalanche Book: A Guide to Staying Safe in Avalanche Terrain, O’Bannon, A. and Clelland, M. 2012. Morris Book Publishing, Falcon Guides, Guilford, CT.

Staying Alive in Avalanche Terrain, 2001, Tremper, B.  The Mountaineers, Seattle, WA.

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