Editor’s Note: This is Part 1 of a four-part series on The Art of Skinning. Contributing Editor John Robison IV explores the backcountry, the culmination for a lifetime of education in the mountains.
Author’s Note: I am by no means a professional, or even all experienced. I’m sharing this partly for selfish reasons — to drill it all down while it’s fresh — and partly to share my perspective as a freshman backcountry rider for those who are interested in getting into backcountry skiing. This is not a comprehensive work, merely an introduction to an immense and complex subject.
Photo: John Robison IV
A profound respect for the mountains was introduced into my way at a very early age. I learned that there was nothing to be conquered ; the mountain will be there tomorrow no matter what. I also learned to love to sensation of safely traveling in the mountains — the freedom and exhilaration and sense of self-reliance that can be gained through intelligent and thoughtful backcountry travel. It is a grounding moment to realize that, in the event of an accident, you are betting your life on the people you’re with and their ability to have and use their tools fast enough to save you.
No friends on a powder day? Only as far as the resort boundary.
Despite a longing to explore the furthest reaches and deepest corners of the mountains , the wintery alpine setting was off-limits to me, and very intentionally so. I drew a line across the boundary of experience — one which I would toe occasionally (on my more brash summit attempts) but made a point not to cross in belligerence. I knew that I, in fact, did not know. Thereby I made the decision to limit my backcountry travel to the summer months.
Until I educated myself on proper backcountry travel techniques in winter, the sparkling untracked just out of bounds stayed that way: out of bounds. However, this winter I pursued that knowledge.
Photo: John Robison IV
Snow in the Mountains
Water makes the world go round. Without this simple little molecule in such abundance, our planet would be very dull indeed.
In the early 1990s, mountain guide instructors Karl Klassen and Jean Pavillard met climbing in the California Sierra. They wanted to standardize national avalanche awareness training — they saw uneven knowledge in the guide candidates they were teaching as backcountry recreation was gaining popularity. And so they formed the American Institute for Avalanche Research and Education, or AIARE.
Since then, the AIARE Backcountry Avalanche courses have become the standard for backcountry travelers in the United States. They offer three levels of courses: Avalanche 1 for recreationalists, Avalanche 2 and 3 for enthusiasts looking to deepen their knowledge or apply it professionally. I took my Avy 1 course in February with the Telluride Avalanche School, the local AIARE course provider. And I was lucky to have the opportunity to put it to use just a week later on a skinning trip in the Beartooth Mountains near Cooke City, Montana , but more on this later.
Photo: John Robison IV
The overall take-away from the AIARE Avalanche 1 Class was this: this earth is complicated. The mountains, especially, are incredibly complex and intricate places and despite our ability to make inferences based on their tendencies, even the most simple-seeming situation could be confounded by any number of variables. There are very few hard-and-fast rules; every situation is unique and conservatism is the best policy.
Broadly, the factors at play in the mountains include precipitation, temperature, the aspect and angle of the slope, the direction and strength of the wind, terrain characteristics (trees, rock outcrops, etc.), cloud cover, humidity, time of day, and so on. Some of these factors are fixed (consider slope angle ) but some change constantly throughout the year, further compounding the complexity that can arise.
All this is essential background and lead up to the critical topic: avalanches. As snow falls, each flake adds to the load, supported by the underlying layers as well the ground. Increased buildup lead to instability on a slope which, once triggered, results in an active release of the snow load. Once this process begins snow slides until it comes to rest, depending on the terrain.
As you can imagine, certain slopes are much more stable than others. The unstable slopes can slide of their own accord or by adding some stress, some trigger. A 170-pound snowboarder dropping in over the steepest part of the slope could be that perfect trigger, especially when combined with new snow, a warm afternoon, or an unstable base.
Anyone who has skied at a resort more than twice knows that snow conditions can vary wildly. This variation depends very much on the factors described above. It’s amazing to see a storm drop two feet of perfect blower pow and then to watch it turn into icy sheets after a single warm day. Or to notice what was soft and pillowy powder in the trees turn to crusty old snow ten feet before the edge of the forest because the lowest part gets sun that the rest of the slope doesn’t.
The point is, we’re helpless. Well, not helpless, but almost. People who spend their entire lives studying snow science and the characteristics of avalanches still die in the mountains every winter. Risk is a given out there; the question is how to mitigate it.
In my view, avalanche education can fall into two broad categories: Avoidance and Reaction. But first, a little background on avalanches.’
Photo: John Robison IV
Types of Avalanches
There are two main types of avalanches, each with a few sub-types. These avalanche types and their characteristics were a critical piece of the Avy 1 curriculum, for good reason. Snow sliding down the mountain can kill you, and your best chance to avoid those avalanches depends on an understanding of the interplay of snow, terrain, and weather conditions.
Loose Snow Avalanches
Loose snow avalanches form when unconsolidated surface snow slides. These tend to happen in dry snow soon after a snowfall event (dry loose snow avalanche) or in wet snow during warmer weather, when the surface layers of the snowpack melt and lose cohesion (wet loose snow avalanche). Loose snow avalanches are easier to predict than slab avalanches — they have a more specific set of conditions required to be triggered and are more easily identified. That said, I’m not sure I’d care just which classification of avalanche it was if I was buried and couldn’t move…
Both wet and dry loose snow avalanches are characterized by an inverted “V” shape, an arrow pointing up the fall line. This is because there is usually a single point of origin, some little snowball that gained some momentum and started picking up more and more snow as it slid down the slope. The most picturesque slides are the dry snow avalanches; the “Vertical Limit” billowing powder clouds only really happen under very specific circumstances. Wet loose snow avalanches tend to move a lot slower, almost like a landslide, and can freeze cement-solid the instant the snow stops moving.
Both types of loose snow avalanches can be enormous and deadly.
Slab Avalanches
Slab avalanches are the most deadly and more difficult to predict. A slab avalanche occurs when a single unit of cohesive snow , a slab, breaks away from the snowpack and slides down the slope. As it slides it breaks up into smaller and smaller chunks, finally coming to rest in the deposition zone. Slabs can form a number of ways. Identifying such “loaded terrain” is a massively important skill to develop if you want to avoid being caught in these dangerous slides.
Wind slabs can form any time there is blowing snow and suitable terrain. As wind blows over loose powder snow, the force of the wind is stronger on the “windward” (upwind) slopes and weaker on the “leeward” (downwind) slopes. Snow particles are more likely to be picked up from the windward aspects and deposited on the leeward ones. As these deposits stack up wind slabs form, basically big piles of snow on the downwind sides of ridges. If these slabs are deposited over a weaker layer of snow they can break free and slide.
On approach to Goose Lake, Montana. Notice the wind-sculpted features on the right. Photo: John Robison IV
Storm slabs are similar to wind slabs in that they form when a large amount of snow is deposited in a short period of time , this time by a storm event. If a heavy layer of snow falls over a weaker layer storm slab avalanche danger is increased. This combined with the powder fever we all get while watching a storm drop a foot or two makes for a very dangerous situation.
Wet slab avalanches can slide in conditions similar to wet loose avalanche, such as warming temperatures and the presence of liquid water in the snowpack. They’re more common in spring and during rain events. These avalanches often trigger later in the day, when the sun has warmed snowfields on certain aspects. For this, the timing of travel in the backcountry can be as important as route selection.
Certain weather and temperature conditions can create weak layers that persist deeper in the snowpack, forming a persistent slab or deep slab hazard. On calm, clear, cold nights, a phenomenon called “surface hoar” can occur. Surface hoar is essentially dew freezing, but as it does feathery crystals grow from the snow surface. If these are buried delicately in the snowpack (say, by a day or two of light snow) they can form a persistent weak layer — once enough weight builds up the crystals can collapse and form a very slick surface for overlying slabs to slide on.
Photo: National Avalanche Center
Alternatively, crusts formed by a period of warming can create a similar weak layer, as can the formation of “faceted” snow, the sugary snow crystals that form over long periods of cold weather. These crystals do not bond with other facets very well, making for an unstable layer and potential persistent slab hazard.
The key takeaway here is that changing conditions increase avalanche risk. So many factors are at play, it is impossible to always be perfect in predicting which terrain might slide.
Photo: John Robison IV
Avoidance
The backcountry traveler’s best policy is to avoid terrain prone to avalanches. This takes the development of a keen eye for that terrain, as well as for viable and safe alternate routes up an objective. Most every trip into the backcountry will begin with a planning session at home. Here the team will discuss the most current avalanche forecast, along with expected weather conditions for the day. These forecasts are the result of a great deal of work and expertise on the part of the often-volunteer avalanche forecasters, and should be regarded very carefully. The forecast will usually include an assessment of the most avalanche-prone terrain, along with an analysis of the most likely encountered avalanche problem. Every region has their own avalanche forecasting service — know it well.
Armed with this knowledge, the backcountry traveler can make decisions long before skins are on at the trailhead. Certain slope aspects will be discussed on the forecast ; these refer to the direction on the compass that a slope is facing, a characteristic that is hugely important in the formation and development of snowpack. For example, southern and western aspects get a lot more sun than northern ones here in the northern hemisphere, a fact that will dramatically change the snowpack as compared to other aspects, even at similar elevations.
Slope angle also plays a major role — perhaps the major role — in whether or not a slope is avalanche-prone. Steep black diamond terrain, (35 to 40 degrees) is the most avalanche prone, but slabs and loose slides do occur at steeper and milder angles. The wise backcountry traveler will use tools available to measure slope angle rather than estimating it; there are even free smartphone apps that will do the trick.
It is also important to bear in mind what is above, as well as below. Hiking in a flat valley bottom might seem safe, but if a major slide path is perched precariously above it may actually be the most dangerous position on the mountain. Contrarily, hikers on a benign slope above a dense forest or cliff could be in grave danger . If they were caught in a slide they would fall directly into these dangerous “terrain traps”.
Amongst all this, certain terrain characteristics can indicate weaker points in the snowpack, called “trigger points”. Imagine a uniform slope with several varying layers of snow that have built up over the winter. These layers bond together, vertically and horizontally, disruptions or stresses in the layers represent their weakest points, where failure is most likely. Rock or tree outcrops provide such a break in the layer and represent potential trigger points. The snowpack is also potentially more likely to slide if subjected to strong forces, say, just below a cornice or cliff where snow or rock is likely to fall and impact the surface. Finally, terrain features known as “convex rolls” represent a stress point in the snowpack, or where terrain steepens dramatically, placing a skier on the crest may be just what an avalanche needs to get started.
And so we’re starting to glimpse the complexity of this subject and gain an understanding of why I’ve been so tentative to step out of bounds in winter.
Photo: Andrew Arseev
Reaction
Avoidance is king in the backcountry, but no traveler is prepared to head out of bounds until they’ve also proven themselves proficient in the reaction to an avalanche. This means mastering the equipment required — the beacon, shovel, and probe — and becoming practiced in their use.
The moment a slide occurs, the clock starts. A balance must be struck. Response must at the same time be rapid and efficient but also calm and collected. Most victims rescued within 15 minutes of burial live, but after that short window survival rates drop off dramatically. If the victim survives the actual slide (i.e. doesn’t suffer deadly trauma) usually they have 15–30 minutes of air before they begin to asphyxiate, especially if they created an air pocket or have an AvaLung. Much longer and hypothermia becomes a concern. Of course, once uncovered the rescue process has only begun; it can be extremely difficult to extract an injured person from even the most accessible backcountry lines. Wilderness first aid skills are essential to any backcountry travelers skill set.
If you are caught in the slide, the goal is to draw attention to yourself while either exiting the slide path or at least keeping some part of your body above the surface of the avalanche, especially when it comes to rest. Yelling out to your team will allow them to fix a “point last seen”, potentially making rescue much more rapid. Partial burials have a much lower fatality rate, so swim and fight to stay on the surface of the snow. Protect your body by discarding equipment and orienting yourself so you are moving downhill feet-first. As the avalanche begins to slow, extra effort to move to the top could save your life. Use your hands around your face to form an air pocket — once the tumult stops it could be impossible to move. Once stopped, maintaining calm is critical. If you can dig yourself out, even a bit, try, but often victims are immobilized. Keeping composure will improve survival chances and the ability to act once you are dug out.
If you are outside the slide path, make sure you’re in a safe position. Avalanches can be triggered remotely, so look around and make sure you won’t become another victim. Watch the avalanche happen and try to catch sight of anybody caught. Fixing their last point will be a major advantage once you start your search: you only have to worry about searching from that last point down the hill. If it is easy, alerting rescue services of the situation quickly could be a benefit; however, it will be up to you to dig out any buried victims, so don’t let a compulsion to call 911 distract you from the most important task at hand. Be prepared with the location, names of the party, the nature of the emergency, as well as any more details that might help professional rescuers in their effort.
As in any emergency situation, how rescuers react can mean life or death. Some leader must be established, and quickly, so each task can be delegated and so someone has the big picture in mind. Take a head count to determine how many are missing, then assign someone to call for help if it hasn’t been done already.
At this point, the rest of the group should begin their search. It is utterly critical that every rescuer switches their avalanche transceivers to “SEARCH” mode; if someone forgets, all other transceivers will point to theirs first, wasting precious time. From the point last seen, search for the transceiver signal and for visual cues — a glove on the surface, a half-buried ski, and so on. Searchers should be spaced about 30m apart and traverse the entire width of the slide path before descending to the next area to scan. As soon as someone picks up a signal, another searcher should join them and follow the transceiver signal to the target area.
It is important to keep the transceiver oriented carefully. Jostling or turning the transceiver upside down could cause the signal to be lost. Follow the signal carefully as the numbers indicating distance to the burial decrease.
As the searchers approach the burial site, the numbers on the transceiver will continue to decrease. At their lowest do a fine scan to find the point on the surface that is closest to the victim. Once this is assured, probe in an outwardly radiating spiral about 25 centimeters apart until the probe strikes the victim. Leave the probe in the strike hole, it will be your only marker of exactly where the victim lies.
At this point the team should be together and working with shovels to dig out the victim. Rather than digging from directly above, though, move downhill and dig in from the side, it will make recovery and treatment much easier once the victim is uncovered. Speed is important here, but frantic action will cause more harm than good. Once the victim has been uncovered find their face so they can breathe, uncover the rest of their body, and assess their condition: they could have life-threatening trauma that needs to be treated before evacuation can begin.
Obviously this is a difficult and complicated set of procedures to follow even in the best circumstances. Now imagine you’re high in the mountains, freezing cold, in low visibility — preparation is the only way to maximize chances of survival in situations like these.
Photo: John Robison IV
Be sure to check in next week for The Art of Skinning, Part 2: The Equipment.
