If you are in the hole and decide to try and climb use a prusik loop attached to the rope with a Klemheist or a classic prusik knot and clipped into your harness with a screwgate crab. Slide this as high up the rope as you can. Next, attach another prusik below it, using the same type of knot, take an 8ft sling and larks-foot this round one or both of your feet and clip it into the prusik.

You may need to tie a knot in the sling to shorten it. Slide the lower foot prusik up the rope until it is just below the top prusik then stand up in the sling at the same time sliding the upper knot up the rope. Gently weight the upper prusik and repeat until you reach the edge of the crevasse. If you have to climb a long way it is worth tying yourself into the rope at intervals to keep you safe if your prusik fails. Taking your sac off and clipping it to the rope loop below you can make climbing out easier. You may have to work really hard to get onto the surface as the lip of the crevasse may be overhung.