Letting It Slide | Why This Season’s Avalanche Statistics Have Been So Concerning - Mpora

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Letting It Slide | Why This Season’s Avalanche Statistics Have Been So Concerning

With widespread resort closures, we take a look at some of the factors leading to the disproportionate rise in avalanche activity this winter

The following article has been put together by backcountry guidebook author Jordan Tiernan (Mpora) and snowboarding coach Rob McCreath (Whitelines). The purpose is to highlight the complexity of avalanche risks and to look at the myriad of factors that all come into play. It is not looking to assign blame or give specific reasons for each incident, as there is no ‘one size fits all’ approach when it comes to avalanche risk. Even so, there are important lessons to be learned from the recent spike in avalanche activity. This article intends to shine a light on some of them.

While avalanche forecasting and moving through potential avalanche terrain is not an exact science, the statistics on their triggering and survival rates are. 90% of avalanche victims release the slide themselves or have it released on them by another member of their group. If they are not found within 15 minutes (and assuming they have not succumbed to any trauma), survival rates drop off rapidly, down to 20-30% after 45 minutes and virtually 0% after two hours

So, why is it that we’ve seen such an alarming amount of human triggered avalanches and, tragically, fatalities despite the lower numbers of people in resorts this year? The answer doesn’t lie in one specific component. Instead, we’re witnessing a kind of ‘perfect storm’ moment and the combination of various red flags.  

 

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There are a number of factors which contribute to the increased risk of avalanche activity: recent snowfall, wind, temperature changes, the shape, aspect and steepness of the slope and, of course, the all-important ‘human’ factor.

However, this season has seen an additional spanner thrown into the works. Its impact has been felt by virtually everyone around the world and disrupted the norms of every aspect of life – even far from the crowds, on snow-covered alpine peaks.

“We’re witnessing a kind of ‘perfect storm’ moment and the combination of various red flags”

We’ve reached out to various experts, from mountain professionals to resort locals based in the Alps, to get their thoughts on the current conditions in the mountains; how they’re mitigating the risks, advice for anyone getting into the backcountry for the first time this season, and how Covid-19 has played such an important factor.

Weather and Snowpack

Early season conditions often bring unsettled spells of weather and a notoriously unstable snowpack. This winter has shown us exactly this again. Steep skier and UIAGM mountain guide Tom Grant reported that “some early season week layers became evident in the snowpack originating from the substantial October snowfall we had followed by a prolonged dry spell.”

“Snowpack conditions have varied from valley to valley, let alone the entire Alps”

Snowpack conditions have varied from valley to valley, let alone the entire Alps, over the past few months, so we’re going to deliberately keep snowpack conditions vague. What we do know, however, is that an extremely weak layer of depth hoar was formed following this prolonged period of calm weather.

Essentially a fancy name for sugary or faceted snow, depth hoar grows within the snowpack due to a large temperature gradient between the warm ground below the snow and the cooler air above the snow. Based on Canadian and Swiss statistics, buried hoar crystals account for more human-triggered avalanches than any other weak layer.

As avalanche expert Bruce Temper says, “Today’s surface hoar is tomorrow’s weak layer”. Similar to a deck of cards holding up the snowpack that falls on top of it, when depth hoar is formed in the middle of the snowpack, all it takes is the weight of a rider, or a rider’s turn to ‘snap’ the energy contained within that weak layer. Classically identified as a “whomph” sound, this weak layer results in the bond between the two snowpack layers releasing, resulting in an avalanche.

“Buried hoar crystals account for more human-triggered avalanches than any other weak layer”

Depth hoar was observed within the snowpack local to Tignes after taking a look at the bed surface of many of the large avalanches observed in resort. While we must stress that factors look to be varying from valley to valley, this can be seen as a key contributor to the high level of avalanche activity in recent weeks. Tom highlighted that “large snowfalls have overloaded some of these slopes making them sensitive to skier triggering. There have also been large natural avalanches.”

Snowpack Consolidation

Following constant weighting of weak layers in a snowpack, these layers, over time, become bonded. Snow consolidation can come in many forms; natural forms such as melt-freeze cycles solidifying the layers, or unnatural forms, such as skier compression (the weight of hundreds of skiers constantly skiing over a layer, in turn, compresses the layer down into the one below), or even a gazex blasting the layers out.

Put simply, there had been very little skier compression throughout the start of the season. Resorts like Tignes and Chamonix, which usually see thousands of skiers passing over their popular off-piste itineraries in any given month, have now only seen just a few descents. This meant resorts essentially had a similar snowpack to far-flung backcountry descents – totally fresh, uncompacted and holding a bucket load of energy. In Chamonix in particular, Tom saw that “the usual skier compaction has meant that these [weak] layers have remained more intact than normal.”

Descents usually considered “safe” now pose serious risk (Credit: Jordan Tiernan)

While resorts across the Alps have seen pisteur (ski patrol) teams controlling the most dangerous of slopes, because resort closures and staff layoffs there hasn’t been nearly as much control work going on in and around resorts. This essentially magnifies the remoteness of many of the descents around resorts that are usually considered ‘safe’.

Resorts are brilliant spots for backcountry novices to find their ski touring or split boarding legs. The above skier compaction, regular patrol sweeps and avalanche control measures mean that backcountry beginners can dip their toe into the world of backcountry skiing and snowboarding, without being thrown into the often unforgiving world of ‘real’ backcountry skiing.

“It was obviously going to be incredibly dangerous… But in a year where the routes aren’t being continuously skied to bond the layers, it was even worse”

This, however, was not the case for the current season. With limited avalanche control and skier compression, as well as fresh snow everywhere, it was all too easy for backcountry skiers – expert or beginner – to find themself what is essentially a serious backcountry descent just minutes from the comfort of the resort.

Simon Perry, co-author of the Tignes Backcountry Guidebook, put the recent dangerous activity to a combination of these factors: “Wherever we were skiing last week we found buried hoar everywhere – even on south faces as low as 2,200m. We were being incredibly careful before the dump, but after so much fresh snow landed on top of the weak layer it was obviously going to be incredibly dangerous – even in a normal ski year. But in a year where the routes aren’t being continuously skied to bond the layers, it was even worse.”

‘Expert Effect’ vs. ‘Backcountry Beginners’

This season’s shift in consumer trends towards backcountry and ski touring equipment has been pretty staggering. Jones Snowboards are reportedly completely sold out of their splitboard stock. Splitboard specific brands, like Spark R&D, have also seen a surge in their global sales.

It’s not surprising, though. With social distancing being the new norm and many resorts remaining closed for the season, the draw towards earning your turns and riding empty resorts is surely something we can all see the attraction in. 

With Jones Splitboards selling out this year, more people than ever are venturing off-piste (Credit: Jordan Tiernan)

But with the increasing numbers of people going into the backcountry (or in many cases, riding within the untouched resort boundaries), there has been growing concern of more people getting into a dangerous situation and out their depth. 

It’s important not to assign blame, though. In our recent interview with Jeremy Jones, he talked about growing attitudes towards beginners and the so-called ‘expert effect’. “Stop pointing all those fingers at beginners,” he said, “because the so-called experts or people who’ve taken an avalanche course and are now feeling empowered are often the most dangerous, quite frankly.”

“The so-called experts or people who’ve taken an avalanche course and are now feeling empowered are often the most dangerous”

Many avalanches continue to be triggered by those who, whether from a lapse in judgement, or disregard of the warnings, have put a foot wrong in the backcountry. Equipping yourself with the avalanche safety kit and knowledge is only half the battle, applying that knowledge effectively is what counts. And with so many people eager capitalise on untouched lines, another factor comes into play.

Powder Fever

Dragon Lodge’s Will Hughes, a man with no shortage of knowledge and experience of backcountry snowboarding, shared his thoughts on the recent avalanche dangers in Tignes: “When it all went bonkers the other day the risk was four out of five, so people shouldn’t have been venturing off too far,” he said. “The controlled areas were epic and made it so hard to understand why you would go somewhere sketchy.” 

For some, you could simply put it down to lack of experience; for others, it might be a simple case of ‘powder fever’. At some point, we’ve all been guilty of it – even the pros. Swiss rider Mat Schaer recently opened up about a lucky escape last season, when he was caught out in this huge avalanche. In sharing his lessons from the day, he cited “being too fired up” as the first. 

 

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It’s a case of ‘easier said than done’, but being able to keep your emotions in check and your mental game sharp in the mountains is arguably as important as any form of pre-planning before you head out the door. It’s rarely a case of staying indoors until the risk drops, but rather adopting tactics that allow you to ride safely every day. “The increased avi risk hasn’t stopped us riding,” says Rhys Jones, a snowboard coach and backcountry guide based in Tignes, “it’s just dictated where we go. When it’s been high risk we’ve just been sticking to mellow slopes and the pistes.

What does all of this mean? Well, early season conditions have certainly affected the stability of the snowpack in many locations around the world, but that isn’t unique to the 20/21 season. On top of this, there’s the somewhat less tangible impact of Covid-19. It has undoubtedly affected the “normal” in-bounds riding conditions, as well as play a role in the recent spike of people getting into splitboarding, ski touring and snowshoeing for the first time, all of which increases the likelihood of avalanches in areas that would – in previous seasons – have been deemed far less risky. 

“This is not a normal season so normal protocols are not enough. Educate, evaluate and treat everything with caution”

Then, of course, the all-important ‘human’ factor plays a role in some cases, too. Even when we do our part to mitigate the risks, ‘powder fever’ has a tendency to creep back in, even more so when many of us have been off snow for an unusually long time.

Lastly, but most importantly – there is always some risk in these scenarios. Riding off-piste is never 100% safe. Forecasting avalanche conditions and moving through avalanche terrain is not an exact science and, while there are ways to mitigate the risks, they’re never completely avoidable. As UIAGM mountain guide and Chamonix local, Dave Searle, put it: “This is not a normal season so normal protocols are not enough. Educate, evaluate and treat everything with caution. Stay safe!”

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