Great Mountain Days in Scotland. Dan Bailey

      Stob Coire nan Lochan, Aonach Eagach and distant Ben Nevis from Bidean nam Bian (Walk 28)

      Winter hills are a world apart from the ordinary, so harsh and so elementally beautiful that their existence on an overdeveloped island can at times seem barely credible – ranks of white-capped peaks jostling to the horizon; wind-carved abstractions on the snow’s crust, each shadow stretched in the low-slung mid-day sun; dark clouds boiling in ice-streaked corries; Gothic gloom and moments of uplifting joy. Winter trips are the most rigorous of all hill walks, and arguably the most memorable. Just take nothing for granted.

Hazards

Avalanches

      Walkers disregard the possibility of avalanches at their peril, and avoidable accidents sadly occur. Daily avalanche forecasts for five popular mountain areas are provided by the sportScotland Avalanche Information Service (SAIS) www.sais.gov.uk. Although a handy weapon in the hill-going armoury, these forecasts are a supplement to knowledge, not a substitute for it. Snow can fall outside the SAIS forecast season, and many mountain areas are not covered by the service at all. Besides, even the best forecasts are only a rough guide. Personal responsibility is integral to all mountain activities, so it pays to learn a little about avalanches and to cultivate a weather eye for likely trouble spots.

      The necessary preconditions for an avalanche are simply sufficient snow cover and an incline. The snowpack builds in layers over time, each of which may have different properties depending on the weather when it was laid and subsequently. Contact between layers of different consistency can be a point of weakness – windslab lying on ice, for instance. In such a situation a ‘surface avalanche’ may be an accident waiting to happen, just wanting an appropriate trigger to release – perhaps a passing walker. In the hairiest conditions avalanches don’t even need an identifiable trigger. Slides may also occur to the full depth of the snowpack, and here the underlying ground surface may be implicated – smooth grass or rock slabs, perhaps.

      Consider the weather. Rapid thaws are obviously risky. Be vigilant during heavy snowfall, too, and for a day or two afterwards while things settle. All loaded snow slopes may be considered suspect, but there will always be particular danger areas. Winds scour lying snow from windward slopes, depositing it on sheltered leeward aspects to build as cornices at the tops of gullies and corrie headwalls and as windslab on the slopes below; either may mean trouble. Wise walkers scan the weather for several days before a trip, noting both the amount of snowfall and the strength and general direction of the wind. A route can then be planned that avoids likely lee slopes, always bearing in mind, of course, that topography may channel winds in unpredictable directions.

      Here are a few more general rules. Slopes between about 25° and 45° are the most at risk – precisely the sort of angles that walkers tend to encounter. Stress fractures occur more readily where the underlying ground is convex. Ridge crests are generally safer than open slopes, although they might carry substantial cornices, the possible fracture line for which may be surprisingly far from the edge.

      These brief paragraphs inevitably raise more questions than they answer. If there’s no choice but to travel a suspect slope, how should you proceed? How might a victim increase their survival chances while falling with hundreds of tons of snow? In a Scottish context, what are the pros and cons of transceivers, probes and shovels? As a bare minimum some further reading is highly recommended – see Appendix 3; better still would be to take a course on avalanche awareness.

      Cold

      Continental mountains may be much colder than Scottish ones in absolute terms, but they tend to be drier too. The combination of wind and wet for which Scotland is renowned can drain body heat very rapidly, creating a felt temperature far lower than the actual thermometer value. Walkers who are inadequately dressed, soaking wet, tired, hungry or slowed by disorientating weather may risk hypothermia, and not just in winter.

      Shivering is an early danger sign. With a drop in core body temperature of only a couple of degrees from the optimum average 37°C the blood begins to drain from the extremities to conserve heat in the core, making manual tasks difficult and exposing hands and feet to the possibility of frostnip (or even in, extreme cases, frostbite). Coordination and brain function begin to be impaired, resulting in slower progress and poorer decision making. If heat loss is unchecked a downward spiral may set in, eventually leading to unconsciousness and ultimately death. As ever, prevention is better than cure, so eat plenty through the day and carry a spare warm layer and a bivvy bag or group shelter for unforeseen stationary periods.

      River crossing

      Runoff from large areas of high ground may channel into a single water course lower down. As the hills drain during thaws or heavy rainfall, the level of burns and rivers can rise dramatically. After a rainy day’s walk a trickle that was crossed with a simple hop from rock to rock that morning might have risen to a torrent. On meeting a swollen river, a long tiring detour to a safer crossing point is preferable to an accident.

      Treat fast-flowing water greater than knee depth with circumspection. If you’re intent on crossing, never do so immediately upstream of waterfalls or boulders into which you might be swept. Ensure that spare dry clothes and other essentials are sealed in a waterproof bag; undo hip and chest straps so that your rucksack doesn’t drag you under. Wear boots or shoes to protect feet from rolling rocks (a pair of ‘Crocs’ or lightweight trainers can be carried for this purpose). Crossing tactics vary, from linking arms in a mutually supportive team shuffle (largest body upstream) to a no-holds-barred diagonal downstream dash (not recommended). A rope can in theory be used, although done badly it’s a sure way to drown your friends. If things have got to this stage, it’s probably better to think again.