It is mid-December and in many mountains of the northern hemisphere snow has arrived. In the Alps, the avalanche hazard is so high that last week the Mont Blanc Tunnel was closed. Already, in the UK plenty of people have been skiing and ice climbing.
To climb or ski in the mountains means accepting some level of risk, but smart mountaineers and skiers have a strategy. They have courage, but also a good understanding of the environment they are entering.
To help assess the risks of trips in unprotected areas, it is worth referring to Munter’s 3×3 Filter & Reduction Method. Based on data collected in the Alps it is designed specifically for ski mountaineers with a thorough knowledge of avalanches, but it outlines some key concepts and approaches well worth considering even if your understanding is limited.
The method stipulates that Snow/weather, Terrain and People impact on avalanche assessment at a regional, local and zonal level. There are various websites that discuss the Munter Method, as well as Munter’s book 3×3 Lawinen.
Avalanche reports combined with the weather forecast and information from any locals provide a good starting point. Scotland has a daily avalanche bulletin for five key areas during winter provided by SAIS, as do most alpine resorts – French link is here. If visiting more remote areas, where avalanche reports don’t exist, try to glean as much information about what the weather has been doing from trusted locals.
One of the things I learned as a young expedition leader was the impact of recent wind direction and its strength. Even though it may not have snowed for a couple of days, high winds can re-distribute snow. Snow can accumulate on the lee slopes (non-windward side), leading to potentially unstable areas of windslab. On Ben Nevis in Scotland, slopes leading to the foot of technical climbs and higher slopes leading to the summit plateau may be areas to avoid. On such days, choosing a ridge or a buttress with a safe start and exit is a safer option. It is a fact that many of Scotland’s best winter cliffs face north, north-east and the prevailing winds are from the south-west, meaning wind-slab is a common hazard.
Where possible, it’s important to study detailed maps and photos to appreciate the aspect and angle of slopes as well as the ground beneath the snow pack. For example in Coire an Lochan in the Cairngorms, an enormous slab of rock, known as the Great Slab, is a big avalanche threat when the area is loaded with snow or in spring, when melt-water can run between the rock and the snow creating a weak bond. Gathering knowledge about such black spots via books or locals is vital when planning a trip.
The team and its individual members constitute another variable. Who exactly is coming? What is their skill set? How will they work as a team? Understanding everyone’s expectations at the planning stage and highlighting some of the potential hazards ahead provides a good platform on which to build.
A good plan starts at home, researches information and takes into account peoples’ expectations before coming up with a plan, including alternatives. Of course, the evaluation of all aspects continues once you arrive in an area and is refined constantly as you start the journey in the mountains. I will look at that in the next blog.