How to cross a 25 feet wide Crevasse?

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.

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.

posted over 9 years ago

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Benedikt Bauer‭

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