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How to cross a Crevasse when its absolutely unavoidable? What gear/equipment is/are required?
What are the things that one should look for when choosing where to cross?

Is it the hard ice from where I should cross, or is it the snow?

EDIT: I am referring to a crevasse that I may need to cross some point in time during a trek that I am planning around Saser kangri II and Saser Kangri IV. The said crevasses is roughly a 20-25 ft (6 to 7.5 m) wide.

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    I fear that question is a bit broad, as there are many different widths of crevasses from narrow enough to just step or hop across it to a full-grown bergschrund and very different conditions from rock-hard ice to powder snow. Therefore the techniques and equipment can vary widely and a single definite answer might get quite extensive. – Benedikt Bauer Sep 4 '14 at 15:34
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    @WedaPashi Regardless of the size make sure you have the knowledge of how to perform a crevasse rescue and all the necessary gear(Prussick Minding Pulley, Accessory Cord, Anchor...) – AM_Hawk Sep 4 '14 at 16:16
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    Do I guess it right that you plan to go solo? – Benedikt Bauer Sep 5 '14 at 9:13
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    If it's just 6 to 7 meter, go ahead, jump over it and catch the fall with two ice axes in hand. You didn't see the movies, huh? ;) – Wills Sep 5 '14 at 17:13
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    Do this: youtu.be/-ooz0oRoE20?t=43s Just be careful that your arms don't rip out of their sockets, or that your momentum doesn't cause your face to smash against the ice, or that the axes don't blow out of the ice immediately at impact because of the sheer force, or that you don't just bounce off the other side entirely, or... – ShemSeger Nov 3 '15 at 22:08
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A crevasse that wide cannot just be jumped across (unless you're among the top long jumpers of the world), therefore you have only two possibilities: avoid it or build a bridge over it.

Typically such bridges are built using aluminum ladders (cf. image below) that are placed across the crevasse and fixed on both sides. In the ideal case one also builds some handrail rope to hold onto.

crevasse

As you can see from the image such bridges are rather permanent constructions, that need some material (ice screws, rope, webbing slings) to get it properly fixed. Also for a crevasse of 7.5m width you can plan for a minimum of 10m (better more) of ladder to have enough spare lengths on both sides for support and fixation. So this is nothing that you carry up the mountain just for the possibility to need it but you will have to plan ahead to bring the right material. It also requires some time to set it up, therefore such ladders are only of use on points where a crevasse is frequently crossed.

As you say you plan or at least expect to go solo on that trip, you won't have the capacity to carry huge amounts of material. In that case your second best choice will be to find a snow bridge over the crevasse.

As those bridges (and also the snowy edges of crevasses) can look firm while being quite unstable, be very careful with your safety measures. That means, create a save anchor (using ice screws, snow protection gear, or whatever is suitable for the conditions) some meters away from the edge and tie your rope there. Cross the snow bridge while you are belayed by the rope. Once on the other side, create another anchor there and fix your rope here as well. If you can afford, leave the rope there until you return to have an easier traverse on your way back (also take into account that you might need to take a fast retreat). If you can't leave the rope there, cross the bridge back again to your first anchor (of course while being secured by the rope somehow), remove the rope and anchor and get back to your second anchor by crossing the bridge a third time.

You see, the snow bridge variant requires to put your life onto some anchor built into snow with the risk of hanging on a rope somewhere down in the crevasse. You should be very sure to know how to rescue yourself from a crevasse and have the necessary gear with you. So in your situation it would clearly be the best choice to take a detour to avoid crossing the crevasse.

  • Question: How do you get the aluminum ladder across and fixed on the other side? – user8082 Nov 3 '15 at 19:31
  • where was this picture taken? how insane does one have to be to cross a crevasse on alumnium ladders taped together? – njzk2 Nov 3 '15 at 22:16
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    @njzk2 Well, I would guess it's from somewhere in the Himalayas and it is more or less standard for expeditions. And if you have paid some $10k to get onto the top of a famous mountain and invested lots of training, balancing over some aluminum ladders won't keep you off... – Benedikt Bauer Nov 4 '15 at 16:35
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    @April you can fix the ladder sections together and lower the completed ladder bridge across using ropes. The technique is sort of a variant on a medieval castle drawbridge. Then someone crosses over the ladder bridge while belayed so they can fix the far end of the bridge. – Erik Nov 4 '15 at 19:22

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