Avalanche Awareness in Scotland
Avalanches seem a statistically unlikely event for your average hill goer. Indeed only 2% of Scottish Mountain Rescue call outs over a 30-year period were for avalanche (The Mountain Rescue Committee of Scotland, Survey of Scottish Avalanche Incidents 1980-2009. Bob Sharpe & Dave Whalley, March 2010). Despite this rarity, avalanches are high consequence for those involved. It’s understandable that most people cannot relate to the likelihood of being avalanched and its consequences, and instead think of it as something that happens to others. Senior Instructor Derek Bain discusses some of the reasons for these perceptions about avalanche hazard in Scotland, and provides advice on how to avoid them on your winter adventures.
.
.
What Does An Avalanche in Scotland Typically Look Like?
The UK’s rapidly changing weather and the transient nature of the avalanche hazard makes it difficult to observe avalanches. The relatively small scale of the hills in Scotland also contributes to our perceptions of avalanche hazard. Most people assume you need huge slopes for avalanches to occur. In fact, any slope that’s steep enough (think scree slope angle), with even shallow snow on it (perhaps 10 to 20cm of snow), can avalanche. A short bank of snow accumulated in a gully feature 5-10 metres high could be enough to bury a person. For many, avalanches conjure images of huge billowing clouds of air borne avalanches from Alpine-scale mountains. Although we do get large avalanches in the UK, more often they are smaller in scale and appear less threatening.
Given the steep nature of avalanche terrain and our shallow snowpack, any slip or slide could be consequential with rocks and the underlying ground creating potential for additional trauma. This is the most likely outcome of an avalanche in Scotland. Although it does happen, full burial is more rare.
The commonly held perception that only skiers and climbers experience avalanches is also false. Over a 30-year period in Scotland, 49% of avalanche incidents involved walkers. When hiking, we are often moving through terrain that is either steep enough or below ground steep enough to avalanche.
.
.
Understanding Causes of Avalanche Hazard in Scotland
Historically, avalanche research and training has focused on the snowpack, weather, and terrain. However well-educated and trained people were still getting avalanched and many of the incidents were being attributed to human error. There are often many external and and internal factors that affect our decision-making. The process often happens quickly, subconsciously, and without challenge or reflection. This is more often the key reason behind an incident, rather than a lack of awareness or knowledge. The implication is that all humans are vulnerable to making poor decisions that may result in an avalanche, regardless of knowledge or training.
Avoiding Avalanches
In efforts to address the human factor, experts have applied knowledge and tactics from other industries such as aviation, medicine, and the military. Decision Making Frameworks (DMFs) can help novices make good decisions. Most are probabilistic; that is, they are based on statistical analyses of historical avalanches. They identify the circumstances that indicate an increased likelihood of avalanches given current conditions.
These DMFs remove the complexity of analysing the avalanche situation by asking a series of question and scoring the answers. The final score gives a relatively black and white decision on whether to go onto a particular slope or not. These DMFs are relatively easy to use, and statistically they work. However to achieve this they considerably reduce the range of terrain on which we can travel. This is unpopular, as people are bound to get bored of having their fun curtailed without any obvious signs of avalanche. This potentially results in them abandoning using the DMF.
In the UK, we have the Be Avalanche Aware (BAA) process. This isn’t a probabilistic DMF, but it does lead you through a process which helps you analyse the avalanche situation and come up with your own solutions. In addition, the human factor is one of three fundamental considerations in the BAA process. The downside to having the freedom to make your own analysis and decisions is that it requires more knowledge and training .
Using The Be Avalanche Aware Process
The diagram below outlines the process. As you can see at each of the three stages (Planning, Journey, and Key Places), we have three fundamental considerations. Weather and Conditions, You and Your Party, and Mountain Landscape.
.
.
It’s important that you understand that BAA is a process, not an educational or planning tool. Although the Planning stage of the process is the most important, you can’t rely totally on good planning. Beyond that, the Journey and Key Place stages should be continued with the same diligence as the planning. A Key Place is potentially the last point at which you can address, challenge, and correct a potential human error, or decision error.
Planning Stage
At the Planning stage, we gather information that will help us create a route plan that avoids avalanche hazard. Use an array of information sources, including maps, guidebooks, conditions reports, weather forecasts (such as the Mountain Weather Information Service and the Met Office), and crucially the avalanche forecast (provided by the Scottish Avalanche Information Service in Scotland). It might seem obvious, but at this stage you have the most options to identify a journey that doesn’t expose you to avalanche hazard. This might mean not doing a route you want, but instead finding an alternative. Be flexible, and plan to avoid hazard.
Key Places
At the planning stage you also need to identify Key Places. These are locations or perhaps a time in the day where it’s necessary to reconsider the situation due to the nature of the terrain or weather. For example, it could be the transition from non-avalanche terrain into avalanche terrain, which is defined by slope angle. Avalanches will start on slopes between 25 and 45 degrees, and run downhill over steep ground to stop on terrain less than 15 degrees.
Flat ground below start zones can therefore be avalanche terrain; there needn’t be hazardous snow on the ground for it to be classed as avalanche terrain. This is the key to safe travel; we can safely move through avalanche terrain if there is no hazardous snow. However we need to determine if there is, or isn’t avalanche hazard on key slopes within avalanche terrain. This is where we will have a Key Place. A Key Place should be directly linked to a decision that is critical to avoid being exposed to avalanche hazard.
Journey
On the Journey stage we continuously observe the three fundamental considerations and identify whether they match those predicted at the planning stage. If the weather and conditions are as forecast and the party are coping with the challenge of the day, then it’s likely that the route option(s) identified at planning will be appropriate.
Finally, at Key Places we need to repeat the process. If this is before the transition to avalanche terrain, perhaps when approaching a steep slope from above, then this may be your last chance to address human factors and consider any influence on your decision-making. This could also be the first time you can see the steep slope. If you have planned to avoid the hazard and the weather forecast was correct, it’s likely that it will be safe to process, and you can make route choices informed by what you see on the ground and the local weather conditions. However, local variations in wind direction may cause accumulations of hazardous snow in unpredictable locations, thus the need to re-check the situation at Key Places and have alternative route choices for when your intended way head appears too hazardous.
.
.
Summary
The freedom to analyse options and decide independently that the BAA model offers compared to other more probabilistic DMFs comes at a price. Greater knowledge, time, and skill is required to develop expertise and judgement. As a start, I would recommend attending a training course or completing the free online training available here: Be Avalanche Aware | Be Avalanche Aware
Once back at base, reflect on your day and identify any potential learning that could be useful for future days out.
Being avalanched seems a remote possibility but if it happens it has high consequences. The perception that small hills with rapidly fluctuating snow conditions do not have avalanche hazard or serious consequence is false. It’s now understood that the human factor and our decision-making errors are usually the root cause of avalanche incidents. The BAA process offers us an approach to decision-making that aims to mitigate human error. It requires us to use skills that are trainable and take time to develop, and that are often best learned by receiving training from those more experienced.
Around the world, most winter activity enthusiasts consider avalanche training a lifelong journey of continuous learning!