Crevasse Rescue

Attach the loaded rope to an anchor using a French Prussick

Back up the French Prussick by tieing back into the main anchor

Protect yourself by abseil and assess the condition of your casualty. Prepare the edge of the crevasse.

Attach a French Prussick to the loaded rope and run a loop of spare rope through this

3:1 Unassisted Hoist

Crevasse rescue is a technique that occupies a lot of time in mountaineers minds. However the chances of a climber falling so completely into a crevasse that they need to be hauled out are mercifully small. In the vast majority of cases a tight rope and a breathless scramble has most folk back on the surface.

In a worst case scenario there are 3 clear stages to rescuing someone

STABALISE the situation
EVALUATE your casualty & the crevasse
RESCUE

There are a huge variety of techniques and pieces of equipment designed for crevasse rescue. At a very basic level a glacial travel kit should include the following.

2 x prussick loops (1.5m of 5-6mm cord tied in a loop with a double fishermans knot)
4 karabiners including 1 x HMS
120cm sling (anchor)

Pullys and ascenders all make rescues easier but increase the weight that must be carried and the complexity of any solutions

STABALISE

Build an anchor. This could be from an ice axe or two, ice screws, skis, a deadman or a snow stake
Attach the loaded rope to the anchor by means of a French Prussick
Back the Prussick up by tieing the rope back into the anchor with a figure 8 knot and a karabiner

EVALUATE

Approach the edge of the crevasse and establish contact with your casualty. Protect yourself by abseiling on an Italian Hitch on the spare rope from the prussick back up knot
Prepare the edge of the crevasse. If the loaded rope has cut into the edge then dig it out and run it over a trekking pole or ice axe to reduce friction

RESCUE
There are two main hositing systems both with their own advantages and disadvantages

UNASSISTED HOIST (3:1 ratio)
With this system a casulaty weighing 90kg would require a pull of 30kg to rescue them (removing friction from the equation. However to raise them 1 meter would require taking in 3 meteres of rope.

Attach a French prussick to the loaded rope. Loop your safety / abseil rope through this karabiner
Remove the back up knot from the anchor leaving the rope running through the karabiner
Pull (hard) on the free rope
When the Prussicks are nearly touching allow the anchor prussick (red) to grip the loaded rope and reset the other (purple) prussick by pushing it as far towards the crevasse as possible.
Repeat pulling and resetting the Prussick until your casulaty can exit the crevasse

ASSISTED HOIST (3:1 ratio)
A very useful variation if your casulaty is concious, able to help and typically not more than 10m below the surface. The system is identical to the Unassisted Hoist apart from the attachment point for the loop of spare rope.

Lower a loop of your safety / abseil rope with a karabiner to your casualty. They should attach this directly to their harness belay loop
Remove the back up knot from the anchor leaving the rope running through the karabiner
Pull (hard) on the free rope while your casulaty assists by pulling on the strand of rope which is moving downwards towards them
There is no requirement to reset this system but the Prussick (red) can be used to hold the rope if you need a rest.

6:1 RATIO HOIST
If more force is required it is possible to add a 2:1 system to both the Unassisted and Assisted hoists to increase the ratio to 6:1. This requires an additional karabiner and Prussick Loop

Attach the spare end of your climbing rope to the anchor
Attach a Prussick loop (green) to the rope the rescuer pulls on during an unassisted or assisted hoist
Run the rope from the anchor through this prussick and back to the rescuer
Pull hard on this rope. Remember to raise a casualty 1 meter with this system you will have to pull in 6 metrers of rope. You will also need to reset the system far more frequently. However in theory a 90kg casualty will only need 15kg of force although in practice friction and rope stretch will increase this significantly

3:1 Assisted Hoist

6:1 Assisted Hoist