Refreshing your Crevasse Rescue and Snow Belay Knowledge - Part 1
A chance to refresh and to reflect on the complexities of building snow anchors in a crevasse rescue situation.
- Uncoil your rope.
- Set your rope lengths for glacial travel – longer if glacier conditions more hazardous.
- Take coils and tie the coils off, making sure the knot is fixed low, so that a person’s weight comes directly onto your harness and through your legs and then crampons to help arrest that persons fall. Not left high in the middle of the chest so that a person’s weight will pull you off balance.
- Walking along a glacier, separated by a fixed distance along the rope from each other, picking a line as you walk over the glacier so that you try and strike each line of a potential crevasse at 90 degrees.
- But even doing this your climbing partner breaks through a snow bridge and falls into the crevasse.
- Drop down onto the glacier and arrest the person – dig your crampons into the snow and drive the pick of your ice axe in too for extra security. Don’t just go into a sitting position otherwise your weight comes off your feet and you get may get pulled off balance and towards the crevasse.
- Everything stabilises and the person’s weight is now on your harness.
- Shout for help, because there may be help close by and it’s so much easier to dig anchors and pull someone out if there are two or more people on top of the glacier – 3 people is an ideal number for glacier travel with this in mind.
- Start to dig a buried axe belay in the glacier.
- First dig a slot parallel to the crevasse the person has gone into, slightly up-slope of where you are positioned. Don’t over stretch up slope otherwise this will de stabilise your feet and crampons.
- The slot needs to be a little longer than your ice axe and tilted slightly up-slope – this is so that when you bury your ice axe, the weight of the person pulling down-slope on it, will only pull it deeper into the snow rather than potentially pulling it out.
- Make sure also that the front-face of the slot, which is the face down-slope, is as clean and smooth as possible.
- The depth of this slot is also important, too shallow, or stopping at a soft layer will mean that when helping pull the person out your ice axe will rip out and the belay will fail.
- Dig down and into solid snow and only stop when you find solid snow, which you know will support the strain of an ice axe pulling against it. You’re actually just trying to dig down. parallel to the crevasse, to find a firm layer of snow to wedge the ice axe against to support the weight of a person.
- This is the most important part, how far down should you dig and what if you can’t find any solid snow? Then you’ll need to bury a backpack or something to create a bigger surface area so that you can get some sort of security from the snow you have.
- By now you’ve dug your initial slot, it’s parallel to the crevasse, it’s been dug deep enough, the slot tilts back up-slope a little and it’s long enough to bury your ice axe length ways.
- Next as the image shows, with the spike on the end of the shaft of you ice axe, rake out a narrow slot in the snow (which only needs to be shaft width) 90 degrees to the bigger slot that you’ve initially dug, directly towards and again at 90 degrees to the crevasse the person has fallen into.
- It’s important that this slot is the same depth as the bigger slot that you’re going to bury your ice axe into. If not, then as the weight comes onto your buried ice axe, the step down in the snow from the thin narrow slot to the deeper bigger slot and onto your ice axe will lift the ice axe to the same height and this might rip the axe out, in the initial movement or because the axe is now pulling against softer or weaker snow, rather than the snow layer you’ve intended for the ice axe to pull against.
- You’ve created a ‘T’ shape slot deep enough to find and in solid snow.
- When digging these two slots try not to upset, kneel on or dig about in the snow down-slop of the wide parrel slot. You can image the person’s weight is being pulled against two snow bollards in effect and if that snow is disturbed then the strength of the snow belay is going to be greatly reduced.
- Now take a long (120cm) sling off your harness, leave the screw gate karabiner attached and tie a clove-hitch knot around the shaft of your ice axe.
- Turn the ice axe around so that the head of the axe is closest to you, and the spike on the end of the shaft is facing away from you.
- Slide the clove hitch up the shaft of your ice axe to roughly the ice axe’s balance point – the reason for this is that you then have roughly the same surface area of ice axe on each side of the clove-hitch, which will pull against each side of your snow anchor giving you maximum security.
- Now, take an extra wrap of sling around the ice axe shaft, so that the clove hitch knot (the point where the sling crosses) sits at the back of the shaft. This means that when the sling is outstretched and is pulled tight, the clove hitch tightens up around the shaft. Without the extra wrap of sling around the shaft, when the sling is outstretched and pulled tight, the knot is secure, but it doesn’t tighten up as well around the ice axe shaft. This means that the clove hitch could potentially slip one way or the other along the shaft, if the ice axe moves for any reason e.g., the initial slot dug to accommodate the ice axe isn’t exactly parallel to the crevasse and so the clove hitch is being pulled at a slight angle under the weight of the person in the crevasse.. Any movement of the ice axe could upset its placement and cause it to fail.
- Check, is the initial ice axe slot parallel to the crevasse? Is it dug deep enough into firm and solid snow? Is the down-slop face of the initial slot smooth for the ice axe to pull against? Is the second slot which accommodates the sling at 90 degrees to that first slot and directly in-line with the pull of the persons weight in the crevasse? Is that second slot the same depth at the first slot – you don’t want a step down into that first slot otherwise it will lift and upset the ice axe when weighted.
- Now with the head of your ice axe closest to you, bury your axe (pick facing downwards) into the slot you’ve dug, so that the clove hitch and sling line up with the downwards slot, which you’ll open up and lay the sling in, with the screw gate karabiner now on the very end closest to the crevasse.
- If you now put some downwards directional weight onto the sling, in line with the downwards slot, the sling will tighten around the shaft of the ice axe. With each slot being the same depth, the weight will come directly onto the ice axe and without any movement or lift the ice axe will pull against the snow bollards you’ve essentially created and not be disturbed, creating a buried snow anchor.
- Now this is the scary part! – gently transfer the weight of the person you’ve been holding in the crevasse onto the snow anchor you’ve created.
- Firstly, take a prussik or Ropeman (or other mechanical friction locking device like the Wild Country Ropeman) off your harness and fix it to the rope going down to the person in the crevasse (if using a prussik, use a French prussik knot).
- Now clip the Ropeman or French prussik into the screw gate karabiner on the end of the sling and push it down the rope towards the crevasse as far as you can reach.
- Now, very gently and very slowly, roll over holding the person’s weight whilst transferring that weight initially to your front points, as you’ll need to step down fractionally for the persons weight to be transferred onto the screw gate karabiner, sling and buried axe.
- I say gently, because it’s critical to make sure that your axe doesn’t move, your axe isn’t being pulled upwards but has a downwards force onto it, and the snow that you’ve dug into is solid enough to take that person’s weight. You need to keep eyeballing your buried ice axe as you’re doing this.
- Once their weight comes onto the buried axe and you’re happy with it, then slowly and steadily, shuffle downhill until all the weight comes onto the snow anchor and as you do this their weight will come off of you. At this point you can then start to take off your coils and unravel the rope so that to can leave the snow belay and go to the edge.
- To do this safely, tie a classic prussik onto the ‘live’ rope (which is the rope from your snow anchor to the person in the crevasse) and then clip yourself into the prussik. Slide the prussik down the rope as you now move towards the crevasse edge. This will protect you from falling down another crevasse between the snow anchor and the crevasse the person is in, as well as backing up the snow belay in case the rope fails.
- By the time you get to the edge of the crevasse, hopefully the person who has fallen into it will have prussiked up the rope and be near the lip and just need a small amount of help getting over the lip and out. Prussiking up a rope to get out of a crevasse is by far the best and safest way to get out. Hanging from a rope, getting into a position to prussik and then prussiking up a rope is a great skill to practise and can be done at a crag or anywhere you can drop a rope down safely.
The whole process does need some instruction and coaching, as there as many elements to it and safety issues to consider and a huge amount of judgement needed. As an example, in the picture you’ll see that I’ve attached a back-up rope to the person demonstrating the initial elements, as discussed above around a crevasse recue scenario. That back-up rope is initially on the person holding the fall in case they don’t hold it, and then gets attached to their snow anchor in case the ice axe rips out. And then there is the even bigger question around the quality of snow, what constitutes as good, firm or solid enough snow, which will hold a buried ice axe in this way.
If you play around and make buried ice axe belays, you’ll be amazed at the strength of a well-made snow belay in good snow.
It’s important to practise arresting a fall, making snow anchors and understanding the mechanics around the complete picture. This will give you so much more confidence and understanding and in turn having a respect for the rope work skills needed when walking on glaciers.
ISM teaches these elements and much more on our Level 1 - Summits & Skills 4000m six-day instructional course, which is a great foundation to summer alpine mountaineering.
If you need a refresher, then also check out our Level 2 – Classic AlpinISM instructional course.
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