Arctic health & safety: Crevasse rescue

CREVASSE RESCUE

Anchor and loosen

The crevasse rescue protocol assumes the following:

-There are at least 3 climbers strung together in a “rope team”. The front climber falls into a crevasse.

As soon as the front climber (no 1) falls into a crevasse, the warning “falling” is shouted. All climbers (no 1, 2, 3) self-arrest. That means they fall immediately on all fours, facing away from the crevasse, with their ice picks dug into the snow, bracing their bodies against any movement, digging their knees and boots into the snow, or their crampons if they are wearing any. They ensure that the rope runs between their legs while standing “dog-style”. The goal of this is to stabilise the faller (no 1), stabilise the rope and to halt any further movement of the rope.

The next priority is to get other anchors, thereby freeing climbers (no 2 &3) from the rope. There are two types of anchors; an initial, fast but not-so-safe ice axe anchor; and a second, time-consuming but safer anchor called a “dead man”, “bomber anchor” or “snow bollard”

While both climbers (no 2 and no 3) are bracing they should attempt to communicate with the faller (no 1). Is the faller hurt? Is the faller dangling in mid-air or is the faller on a snow bridge? Can the faller climb out on own steam? Can the faller see another route by which one can just walk out?Does the faller have two hand tools to climb out of the crevasse? Can the faller prusik up the rope?  Must the faller be pulleyed out? If there are multiple rope teams it may be possible to pull the faller out by brute force. If the faller is too heavy or unconscious a pulley system will have to be built.

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The initial fast ice axe anchor is done in the following way. The climber furthest (no 3) from the dangling faller (no 1) must attempt to loosen themselves from the rope. This can only be done when there is proof that climber (no 2) can carry the weight of the faller. The distant climber will have to prusik their way to a position halfway between the second climber and the lip of the crevasse. Because the prusik is used continuously any movement on the rope will make all in the rope team brace themselves in the “brace” position after “falling” command.

No 3 drives an ice pick anchor into the snow. Because this is not a very safe anchor climber no 3 has to protect the ice pick anchor with their foot. A small rope is applied to the pick, to a carabener; to a prusik to the main rope. As soon as there is better safety, the “dead man anchor” must be built. The initial anchor’s ropes and the dead man anchor’s rope must always be inferior to ( beneath) the main rope.

If there is safety with the ice pick anchor (with one foot stabilising the pick), no 2 can be freed off the rope. No 2 can take over the job of stabilising the ice  pick anchor. No 3 can start digging the “dead man”. This is a trench 2 foot deep, running longitudinally with crevasse lip. A gutter can be ripped into the trench via a snow saw creating a T-configuration. A double banded rope can go through this cleavage. Skis or backpacks can be used as counterweight in the “dead man”. A double line is connected to the carabiner where the ice pick is also connected. This means there are now two anchors; one ice pick anchor and one “dead man” anchor.

With two anchors in place a decision can be made on extracting the faller (no 1). A simple pulley or Z-pulley can be constructed. A Z-pulley will give a 3-1 advantage.

Before one contemplates extraction of the faller, the integrity of the crevasse lip must be secured. If the lip is not strengthened the rope will entrench itself into the snow and make it very difficult if not near-impossible to haul the faller over the edge.

Climber no 3 must prusik down to the crevasse lip while prodding with a prod or ice pick to identify any other crevasses (prusiked to the slack part of the main rope) to so as to identify any other crevasses. Before prusiking down the main rope with the slack rope, the figure of 8 on a bite needs to be loosened. On the lip of the crevasse a ice pick or ski must be placed in a shallow mini-dead man trench so that the rope runs over this hardened structure.

Construction of a Z-pulley

Two pulleys must be attached to make a Z-pulley.

The first pulley is prusiked to the two anchors. The taught rope will still be prusiked to the anchors. Loosen the figure-of-8-on-a-bight and rope the slack end through the first pulley. Re-knot the figure-of-8-on-bight and connect it back to the anchors’ carabeener.

The slack end is prusiked to the belt of the N0 3 who prusikes down the taught rope.

The second pulley must be placed as close to the lip as possible. No 3 places a prusik on the main taught rope running to the faller and connects it to the second pulley. No 3 ropes the slack end through the pulley, attaches the rope with a prusik back on his belt and drags the rope back to No 2.

On arrival back at no 2, no 3 disconnects his prusik with the main line. The figure-of-8-on-a-bight must be loosened as well as the back-up safety prusik. The slack rope can now pulled tight and the faller hoisted.

On hoisting the second pulley will migrate closer to the first. When the 2 pulleys are two feet apart, attach a prusik to connect the taught rope to the anchor carabeener and retie a figure-of-8-on-a-bight on the slack end of rope. Hook the figure-of-8-on-bight in the carabeener for triple safety.

No 3 while prusiked to the taught rope, drags the second pulley back to the lip of the crevasse. N0 3 then prusiks back to no 2, the figure-of-8-on-a-bight rope is loosened, the prusik to the taught rope is loosened and the faller is hoisted again.

This is continued till the faller reaches the lip. This is a very dangerous part of the procedure as the faller can get caught under the lip. If the faller is conscious the faller must position himself so that he gets over the lip without getting stuck.

He is dragged back till safely back with  no 2 and n0 3.