Rock fall results in chopped anchor!

PHEW!!! Glad youre okay!

I ponder on a few things when reviewing this. As AMGA guides, why do they not
1. use locking carabiners on anchors
2. use a quad anchor with a limit on each arm.
?

Lockers are not needed to connect a sling to the bolts because there are 2 (or more). There is redundancy in the anchors connection to the bolts. We don't use lockers to contact quickdraw to bolts because there are multiple connections of the rope to the rock as we lead and clip more and more draws.

I do sometimes use a quad.

Here though I am glad I did not. The rock cut the anchor very close to the master point knot.
If I had used a quad and the rock hit on my side of the load limiting knot and cut two legs one or both of us who were at the anchor could or, depending on which two strands were clipped, would have fallen off.

Depends on where the lightning strikes and the material gets cut. Bolt side there's extension. Climbers side you die.

That's a really interesting consideration, and not one I've seen addressed before. Granted, it's a very freak, specific circumstance, but a weakness in the quad that hasn't been recognized. Someone should send this thread to John Long.

This was turned into a podcast through The Sharp End. Great story and worth a listen:

soundcloud.com/the_sharp_en…

cdec wrote:If I had used a quad and the rock hit on my side of the load limiting knot and cut two legs one or both of us who were at the anchor could or, depending on which two strands were clipped, would have fallen off. Depends on where the lightning strikes and the material gets cut. Bolt side there's extension. Climbers side you die.

Isn't that true of your anchor as well? If the two cut strands were below the knot, you also would have lost the anchor. Not sure why that is a failing of the quad... Also, on a quad you could clip 3 strands rather than 2.

The only way I can think of to have complete redundancy and back-up against a cut right at the central point is by using a second sling to connect the biners on the two points and the central one(s), and to have this back-up sling attach to the various biners in other places than the ones occupied by the primary sling (eg with cloves snugged on the spines). But that's the kind of overkill most people scoff at.

steverett wrote: Isn't that true of your anchor as well? If the two cut strands were below the knot, you also would have lost the anchor. Not sure why that is a failing of the quad... Also, on a quad you could clip 3 strands rather than 2.

Took me a while, but picture a quad:


The quad's masterpoint covers a much larger area than a normal equalized 8. The "adjustability" of it also makes it more susceptible to rock fall; there's more things to hit. On an 8, to cut the climber's side strands, the rock would have to basically cut all the way through that big beefy knot, at which point you'd be dead anyways. Let's say in this scenario, a big rock starts falling toward the climber on the left...his impulse will be to lean as far right as possible, stretching to the end of the equalization range and basically being flush with the knot...and exposing a long length of cuttable cord that is inside the other stopper knot.

steverett wrote: Isn't that true of your anchor as well? If the two cut strands were below the knot, you also would have lost the anchor. Not sure why that is a failing of the quad... Also, on a quad you could clip 3 strands rather than 2.

It is for sure and it is not a failing of the quad as an anchor choice. It is simply a consideration.
The difference is that the loop below the knot in a pre-equalized anchor is generally much smaller.

As for clipping 3, when climbing with 2 additional people I like to clip each into 2 sets of 2 different strands. That way there is less shift when one person or the other moves. In the picture each miner can shift freely and not really move the anchor for the other climber.

Then what Ted said kinda covers it.

Please don't get me wrong. There is a place and a time for use of the Magic X, the quad and a pre equalized anchor.

There is no single anchor that is best for all situations. I use all three.

I just wanted people to know that the one in a million happened and that we were relatively OK because of the choices I made. However things may have been very different had I chosen to use another commonly used anchor.

Like I said in the post, in Accidents and on the pod cast. You may want to factor in the risk of objective hazard from above when choosing which configuration to use.

Clipping into three strands of a 7-8mm quad would appear to withstand rockfall better, and slings have enough evidence against being used as anchors, but to each his own as far as level of safety is concerned.

I'm just looking for a takeaway message even though rock fall is common, this is definitely a rare scenario. Thanks for staying safe and thanks for sharing!

Physics argues slings as poor anchors or PAS as they designed for static loads, not fall bearing. I've read several accident reports on failed non-dynamic tethers. The anchor in this specific accident report ended up as a fall bearing tether, although luckily the climbers were tethered in with dynamic rope with clove hitches, which is a good takeaway, however if the anchor is not dynamic, and the climbers use a non-dynamic PAS as well, the danger is great especially in multi-pitch. When cleaning, climbers often clip directly to their anchor rather than use a PAS, and to be safe requires the anchor material be dynamic.

Thanks again for sharing and informing. Stay safe

sling anchors analyzed

Dancho, I'm not sure of the relevance of your post to this thread. While your point is true about static tethers, this principle is less significant when considering anchor material. Think about a QuickDraw; the dog bones are made of very static dyneema, yet sport climbers take 40' whippers onto them without breaking them. Why? Because they're tied into a dynamic climbing rope that absorbs the force. As long as there's a dynamic component in the chain (almost always the rope), you are safe. Think about it: if the whole system had to be dynamic, could we use carabiners?

Finally, it's important to not overstate the dynamic qualities of nylon. Using a nylon tether or anchor cord does NOT mean that it is suddenly safe to fall directly onto the anchor. This is never good, even with climbing rope, as it results in a Factor 1 Fall (or ~2, if you fall past the anchor). So whether you use a sling or cord for your anchor is really irrelevant when it comes to being dynamic, although there are other reasons not to use a sling (strength loss from knots, etc).

The originally described accident seems like a pretty crazy set of circumstances-- very large rockfall directly over the belay, in a way that manages to not kill the climbers but perfectly sever two strands of the anchor. Quite the combination of good and bad luck...