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发表于 2015-2-5 12:00
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失效的保护站
Colin Haley在2014年夏天的事故，他在mt. Robson, solo, 下降用了2个以前别人打的pitons, 他觉得这2个piton有点问题，狠砸之后用它下降。开始一段比较陡基本垂直，后来是大概30度的雪坡。他下到雪坡上继续绳降时，2个piton拔出，保护站完全失效。
分析：Colin认为是后来绳降角度变缓，导致受力角度改变而使得piton被拉出来。
教训：
1. 受力角度对于piton是否靠谱是非常关键的
2. 慢慢匀速降
3. 即使要节约器材，正确的做法是拔出老piton,自己设置靠谱的保护站
原文在此：
http://www.colinhaley.com/minivan-alpinism-in-canada/
Eventually I came to a steep cliff band that, although only about 20m high, I couldn’t traverse around. I went to what looked like the best place to set up a rappel, and low-and-behold, I found somebody’s old rappel anchor: a baby-angle piton and a lost-arrow piton, equalized with cord. The two pitons were placed in a crack that was nearly horizontal, but in fact angled about 5 degrees down (toward the outside). I couldn’t place any cams or nuts as backup pieces, as there were no other cracks. I could’ve placed another piton, but I was concerned about conserving my meager rack for lower down. I used the hammer on my ice tool to whack on both of the fixed pitons – One seemed totally solid, and the other went a millimeter or two deeper. I used a sling and a ‘biner to backup the old cord, and rigged my rappel rope. When I started rappelling I did what I always do on marginal rappel anchors – I kept my weight as low as possible, and rappelled smoothly and gingerly. The rappel was short but vertical to overhanging. Below the cliffband was a 30-degree snow-slope, so when I touched down on that I just kept rappelling, because if the rappel is already rigged it is faster than down-climbing, even on such low-angle terrain. I was quickly rappelling down this 30-degree slope when suddenly I lost my balance and nearly tripped. For a moment I didn’t understand what had happened, and then realized in horror that my rappel anchor had ripped out! As I had gone further down the 30-degree snowfield, the angle of pull on the two pitons had become closer and closer to directly out along the axis of the pitons. The terrain I was on was so easy that I didn’t even fall on my ass, but it clearly was a very close call. I consider this to my seventh way-too-close call in the mountains, and of course I am not proud of it. If the rappel anchor had ripped while I was rappelling the cliff band it’s likely I would have survived the fall, but being half-way up Robson’s west face, alone, injured, without any communication device, on a Tuesday in September, would have been a grim situation.
I’ve made three major conclusions about this close call:
1) The direction of pull is VERY significant in the strength of a piton placement.
2) It is ABSOLUTELY worthwhile to keep your weight low and rappel with care on sketchy anchors. In this case it’s not unlikely that this practice saved my life.
3) What I should have done, considering that I was trying to conserve my meager rack, was remove both of the fixed pins and replace them. That would have cost me a few minutes, but no extra gear, and I’m sure I could’ve placed both pins solidly in that case. |
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