Self-arrest

Self-arrest refers to various maneuvers employed in mountaineering, in which a climber who has fallen and is sliding down a snow or ice covered slope arrests (stops) the slide by himself or herself without recourse to a rope or other belay system.[1]

Self-arrest can be performed by using some combination of a climber's boots, hands, feet, knees, elbows, crampons, and/or ice axe. These potentially life-saving techniques must be practiced frequently in order to maintain proficiency. Use of an ice axe greatly increases the probability of effectively stopping a fall down a snow field, ice field, or glacier.

Self-arrest techniques

Cautionary note:

This article is not intended to provide instruction on how to perform a successful self-arrest. Its scope is merely descriptive in nature. Do not expect to be successful performing a self-arrest just by following the description in this article. Self-arrest should be learned from a qualified instructor and requires repeated practice in order to become proficient at it.

With an ice axe: The most important part of the maneuver is to get into the correct self-arrest position. In this position the climber is in the prone position with feet oriented downslope, legs bent at the knees, and elbows tucked tightly against the torso. The axe is held diagonally across the chest and abdomen, with one hand tightly gripping the head of the axe and the other positioned at the base of the shaft, just above the spike. The head of the axe is close to the shoulder and the pick is buried as deeply into the slope as possible. Once in this position the climber arcs his body so that three critical points are in contact with the slope — the pick and the knees, with as much of the climber's weight as possible on the pick.

This maneuver is easiest when the climber falls face down and is sliding feet first down the slope. If he falls in any other position — face up, feet oriented upslope, etc. — he must first rotate his body, using the pick of the axe as a pivot point, until he is in the optimal position as described above. Self-arrest may be much more difficult to perform in such cases.

Self-arrest grip: To be able to perform the self-arrest maneuver the pick of the ice axe should project away from the body when the hand on top of it is brought to the shoulder. To ensure that this is accomplished as fast as possible, climbers often adopt the so-called self-arrest grip. In this grip, the axe is held in the upslope hand with the tips of the fingers oriented towards the spike at the base of the shaft. The thumb is positioned over the adze, and the pick projects out beyond the little finger. When walking or climbing with the axe held in this manner, the pick points backwards while the adze points in the direction of travel. If the axe is held pick forward, it needs to be reversed in the hand to bring it to bear against the slope. This delays the implementation of the maneuver, and can cause the climber to lose control of his axe.

While wearing crampons: While sliding down a slope, a climber wearing crampons should keep the feet away from the slope, using the knees instead as points of contact. Putting weight on the feet while wearing crampons will cause their points to snag in the ice or snow, potentially causing significant injury to the climber's ankles and sending him/her into an uncontrolled and possibly fatal tumble down the slope.

Without an ice axe: Without recourse to an ice axe, a skilled climber will attempt to orient his body it is in the optimal position as described above, and to put as much pressure as possible on the hands and knees, and (if not wearing crampons) toes.

Effectiveness of self-arrest

Self-arrest is by no means an infallible technique. The likelihood of being able to arrest a slide in this way is estimated to be around 50%, and this depends on three main factors:

The tip of the pick of the ice axe forms a short blade. When there is positive clearance the downhill point of this blade will engage the ice first when the axe is in arrest position. With negative clearance the uphill point of the blade will engage first. On hard ice, a negative-clearance-axe will skate across the surface when attempting arrest, resulting in very little braking force. This has often resulted in very serious injury and death. A positive- clearance point will dig in aggressively, requiring skill to avoid excessive braking force but giving the climber his/her best chance to survive.

Self-arrest as a safety measure

Self-arrest is a measure of last recourse. In general one should not rely on self-arrest to assure safety while engaging a slope. Instead the appropriate techniques of self-belay or roped belay should be used. Mountaineering experts have suggested that use of a dynamic rope and climbing harness without intermediate protection points, as done by roped parties during glacier travel, should be avoided when travelling on terrain with a significant incline. This technique may make self-arrest almost impossible, causing the fall of a single climber to bring down the entire party.

See also

References

  1. ↑ Steven M. Cox and Kris Fulsaas, ed. (2003). Mountaineering: The Freedom of the Hills (7 ed.). Seattle: The Mountaineers. ISBN 0-89886-828-9.

External links