Hilary Sharp, expert mountaineer and holder of the International Mountain Leader award, explains the safest way to travel across a glacier. Part two of the article focusses on Crevasse Rescue Techniques. It pays to be prepared!
In this article, Hilary Sharp explains the safest way to travel across a glacier. It pays to be prepared!
How to Travel Across a Glacier
The principal hazard of travel across a glacier is that of hidden crevasses. On a dry glacier (that is, a glacier not covered with snow) crevasses are obvious and therefore pose few problems. However, on a wet (snow-covered) glacier what lurks beneath the surface presents a very real danger.
Travel on a wet glacier, therefore, is always undertaken roped together – even if there is a good track and good visibility. Roping up wrongly and/or using the rope incorrectly can make any crevasse incident worse. It is therefore essential to adopt correct practice and to keep to certain guidelines. This guide is not intended as an instruction manual, and what follows is more of a reminder. How to travel across a glacier safely and crevasse rescue techniques must be learnt and practised, either on a specialised course or from an experienced mountaineer or a professional.
Each participant should be equipped with the minimum of an ice axe, a harness and screwgate krab, an ice screw, a 120cm sling, three prussik loops, a pulley and three spare karabiners. The party should have a dynamic rope, the minimum diameter of which should be 8mm, although in practice a larger diameter is more user-friendly when it comes to handling in a crevasse rescue situation. It is not necessary to have a designated single rope of 10 or 11mm if only pure glacier travel is envisaged. The minimum length should be about 30m for two people. For larger numbers a longer rope or two ropes should be used.
We will look at glacier travel for a party of two people. The walkers should be roped together with about 10m of rope between them (see Figure 1 below). To do this each should tie into the ends of the rope and take an equal number of coils around their shoulders until the middle 10m is left. The coils are tied off by passing a bight of rope around them and tying an overhand knot around the rope that leads between the walkers. This leaves a loop, which can be clipped back into the harness with the screwgate karabiner.
When walking the rope should be kept reasonably tight – so that the middle 5–6m glide along the snow. If this tension is maintained, not only will the rope be kept away from sharp crampons, it also avoids the dangerous practice of holding the rope up in your hand, the result of which can be a serious shoulder injury in the event of a crevasse fall. Under no circumstances should coils be carried in the hand on a wet glacier.
One trekking pole should be stowed away on the rucksack leaving that hand free for the ice axe. The axe must be instantly available for arresting a fall, not attached to the back of the rucksack. It should be carried by the head, with the shaft downwards like a walking stick, in the uphill hand whenever appropriate.
Two further refinements of this basic system are the pre-attachment of prussik loops to the rope and the tying of knots in the rope at intervals along the 10m. The theory behind the latter method is that in the event of a crevasse fall the rope will cut into the snow lip and the knot will jam into the snow, thus arresting the fall. The downside of this system is that if the snow is very soft the knot will pass right through the snow and will hinder the subsequent rescue.
It is worth considering putting the lightest person at the front as disparity in weight is an important factor, but bear in mind that it’s not always the first person to cross that breaks a fragile snow bridge.
Although both members of the party should be vigilant at all times on a glacier, some particularly crevassed areas will obviously be more dangerous than others. This information should be passed back from the leader so that the second person can prepare himself and tighten the rope further.