The most recent (2013) edition of Climbing Anchors, by Long and Gaines, makes some interesting statements in the preface about catastrophic failures of anchors. Long first says that: when belay anchors fail, it's usually in cases where the gear was placed in a horizontal crack, and the anchor was subjected to a shock load sideways to the intended direction of pull. He attributes this to anecdotal reports. He also says the following, which I find very surprising.

Because statistically, the majority of climbing accidents occur from leader falls, we'd expect catastrophic anchor failure to result from a leader taking the dreaded Factor 2 ripper right onto the anchor. Not so. Most of these failures involved a leader belaying a second up on a toprope.

So from this information, it sounds like these failures often happen the first time the anchor is ever loaded, i.e., it was such a poor anchor that it wouldn't hold even a top-rope fall.

Is it possible to find systematic statistics anywhere on the types of anchor failures (top-roping, leading, ...) and how survivable they were? In the case of the leader belaying the follower, it seems like the failure might actually be survivable in many cases, since there might still be a lot of gear down below that hadn't yet been cleaned. (But the belayer had better maintain a serious death-grip on the rope!) Even if, as Long says, few failures are from factor-2 falls, those are probably the ones that would not be survivable at all, since there is no other gear present.

I'm also having a hard time reconciling the statements that:

  1. "anchor failures are usually from a load "sideways to the intended direction of pull,"
  2. they usually happen while the leader is belaying the follower.

When the leader is building the anchor, his rope is trailing right back toward his last piece of pro, so it should be dead obvious what the direction of pull is going to be when he catches a fall by the follower. The exception would be, I guess, when there is a traverse from the last piece to the belay station, and the follower takes a fall after cleaning that final piece (and in this case, the anchor failure is probably not going to be survivable).

I would also be interested in statistics about how many accidents are caused by anchor failures while climbing, as opposed to rappelling. The latter seems more common, which probably isn't so surprising, since people usually try to make their belay anchors really bombproof.

  • As I read it he's saying that the majority of accidents are from incorrectly set up belays. So the leader has lead the climb, set up a belay for his second to follow. At some point the leaders belay has been loaded (second falls maybe) the gear isn't high enough so is loaded horizontally and pops out. Leader falls. I'm not 100% clear what your question is though. Can you clarify? – user2766 Oct 20 '14 at 12:21
  • Do you have a link to the original article? – user2766 Oct 20 '14 at 12:52
  • I'd suggest emailing John Long to ask; IIRC anchor failures are quite rare, although the 2012 ANAM intro suggests anchor failure accounts for 26% of rappel accidents. (It's also possible the DAV has good numbers on this, if any Germans are reading...) – requiem Oct 20 '14 at 15:28
  • It's very unlikely that a belay failure would be survivable, once the rope has held an initial fall it takes time to become elastic again. Any load after that is essentially static and climbing gear is simply not manufactured to deal with the forces generated by a static rope when falling, google zipper effect. – Fred the Magic Wonder Dog Mar 18 '15 at 16:07
  • @FredtheMagicWonderDog: I do not find anything by googling about zipper effect, can you refer my to a source. That would be the first time I hear about it while it has pretty serious implications. – imsodin Mar 24 '15 at 21:25

Personally, I can easily see how this unintended loading can happen.

Second gets to a tricky part, asks leader for beta, leader moves over to get a better view of second.

This question is an example of one of the really hard problems in climbing. It's almost impossible to get feedback about how well you are building your anchors. You just don't get many chances to be wrong.

99% of the time any protection you place simply won't be tested in any way. Most of the time it simply doesn't matter if you build a crap anchor or a bomber one. If nobody falls or the belayer has a good enough position to hold the fall with body weight, the anchor never gets stressed. It's next to impossible to know if you are good or just lucky.

You can develop or follow really bad practices for a very long time and not suffer any consquences. The America Death Triangle is a classic example. In the 70's when I was learning to climb, that was standard practice in the USA. Everybody I climbed with used it, so I used it too.

Ideally, you'd like to spend time building anchors and throwing dummies off cliffs, but that's expensive in ropes and time.

One way you can get better at building anchors is aid climbing, but that pretty old school these days.

  • Every belay is different, some, you know (think?) you have bomb proof anchors, others, you know(think?) are 'less than ideal' but its the best you can do. I wonder what the correlation between what the belayer thought, and reality, has been studied (although the probable outcome of a belay failure precludes a rigorous study) . – user5330 Mar 18 '15 at 20:22
  • 2
    All the psychology in this situation is bad. Humans have a bias to attribute to skill any positive outcome, regardless of how much random factors determine the outcome. – Fred the Magic Wonder Dog Mar 20 '15 at 14:45

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