Glaciers are water bodies made of dense ice that is continuously moving - rivers of ice - and are formed in regions where accumulation of snow in winter exceeds the rate of ablation (melting). Since they are constantly moving, and riddled with gaps or cracks called crevasses, travel across glaciers requires the knowledge of specific techniques.
Glaciers can be dry - when the bare ice is visible - in which case crevasses will be clearly visible, or wet - covered with snow - in which case crevasses will be hidden.
Most passes in the Indian Himalaya lying above 5000 m are permanently glaciated. Glacier travel is also generally required to access higher peaks.
Note that crevasse falls are a real risk associated with glaciers, and independent glacier travel requires the knowledge of additional crevasse rescue methods, knots, belaying, anchoring and rappelling techniques that we will look at separately in further articles. This article, in isolation, only prepares you for glacier travel under the supervision and guidance of trained professionals.
EQUIPMENT
- Rope: The fundamental principle of glacier travel is that parties must always be roped up. A 50m coil of 9-10mm rope is ideal for a group of 3, or in rare cases, 4 people.
- Ice Axe: Each member of your party will require an axe for probing, anchoring and belaying. A good CEN/UIAA certified mountaineering axe is appropriate. Avoid using technical ice tools since they do not offer appropriate self arrest and anchoring performance.
- Crampons: Always use crampons while traveling on glaciers. They provide superior purchase on ice and are essential in recovering from crevasse falls.
- Prussic Cord: A 5-7mm cord, around 1m/3ft in length. This will be used to tie a prussic or auto block knot to the main rope for backup.
- Harness: A standard rock climbing/mountaineering harness to enable you to tie into the rope, carry equipment, and allow for hauling in case of crevasse falls.
- Helmet: A standard rock climbing/mountaineering helmet to protect you in case of crevasse falls.
- Snow Probe/Trekking Pole: A snow probe is an expandable used to probe the terrain ahead for hidden crevasses. You can also make do with a trekking or skiing pole.
It is common to see trekking parties traveling across glaciers in the Indian Himalaya without the use of proper techniques and equipment. While this may work on short, flat, dry glaciers with a couple of easily negotiable open crevasses which your guide is familiar with, it is strictly not recommended for sustained glacial travel. Moving on glaciers unroped, or without helmets, crampons, axes and harnesses can complicate crevasse rescue in case of a fall and, in the worst cases, even make it impossible.
In addition to the equipment mentioned above, you will also need the following equipment for crevasse rescue techniques. The use of this equipment and the relevant techniques will be discussed in the next part of this series of articles.
- Carabiners
- Pulley
- Descender
- Snow/Ice Anchors
- Additional slings and prussic cords
- Jumar/Micro Traxion/PCD (Progress Capture Device)
TECHNIQUE
Tie-In/Rope-up
The is the first and fundamental step of glacier travel. A 50m coil of rope is appropriate for a party of 3-4 people. This ensures a distance of 12-15m between individuals, which is required to properly execute arrests in case of falls, and maintain some reserve to perform rescue techniques. You may see parties of 5-6 people or more roped up together, but this is highly unadvisable as a single person’s fall will probably cause the entire party to hurtle down a crevasse.
For a 3 person rope, have the person in the middle find the middle mark of the rope. Measure 12-15m on either side of the middle for the other two people. Use a carabiner and figure 8 knot to tie the rope to your harness. The first and last person coil any remaining rope on either side diagonally around the chest. Do not go alone.
Backup
Once you’ve tied in to the rope, use the prussic cord to tie a prussic or autoblock knot around the rope. Prussics and autoblocks are knots that enable you to move up an anchored rope, but arrest any unwarranted downward movement. This will act as a backup, and allow you to climb up a crevasse yourself if it has a low or moderate angled slope.
Rope Taut
It is important to synchonize your movement with your partners’ in a way that the rope always remains taut. The line between taut and tight is tricky to navigate but make sure everyone can walk freely, but no extra slack is introduced into the system by unplanned halts or different walking paces. Any slack will translate to high shock loads in case someone falls into a crevasse and reduce the chances of successful arrest.
Path of least resistance
Try to identify the path of least resistance - generally this means avoiding any big drop offs or steep climbs as steeper parts of the glacier will have more, wider, and deeper crevasses. Stick to low angled slopes or flat parts of the glacier whenever you can.
Probe for crevasses
On wet glaciers, use a trekking pole or snow probe to stab hard into the snow in front of you before each step to probe for crevasses. If the pole/probe stops after going in a short distance and you feel resistance, chances are it will hold your weight. If it keeps going, and you feel you can move it freely, you are probably on a snow bridge over a crevasse. You can also use your ice axe in the cane position to probe, though it’s shorter length will make it uncomfortable over a long period.
Shout if you fall
Shout ‘Falling!’ in case you begin to fall. This will alert your partners rapidly and allow them enough time to execute an arrest. Remember, if you don’t shout, your partners may not know until the force from your fall causes them to lose balance as well.
Time of travel
The snow will be firm and hard during the night and early in the morning, as it has had a chance to freeze. This is the most preferable time for glacier travel. Once the snow starts melting later in the afternoon, snow bridges will have a higher chance of collapsing under you.
Self arrest
Learn how to arrest falls on snow using an ice axe, discussed separately. Without this skill, you will put yourself and others at the risk of your team at risk of falling into crevasses.
CREVASSE NEGOTIATION
- Short open crevasses can simply be jumped across. If you are not sure you will make the distance, have someone belay you.
- If you suspect a hidden crevasse while probing, get down on all fours and distribute your weight. A larger surface area means lesser pressure at any single point on the snow bridge, and lesser chances of it collapsing under you.
- For any wide, open crevasses (like most bergschrunds - the first crevasse separating the glacier from the slope above), you will either need to climb down one side and climb up the other, or need to use ladders, build improvised ladders using ice axes or build a Tyrolean traverse. These are all resource and time intensive techniques beyond the scope of this article.
ADDITIONAL SKILLS REQUIRED FOR INDEPENDENT GLACIER TRAVEL
- Use of ice axe and crampons
- Self arrest
- Knots - figure 8, munter/italian hitch, prussic/autoblock, clove hitch
- Anchoring, belaying and rapelling on snow and ice
- Hauling systems for crevasse rescue
