This has been bugging me for a while. A party is traveling on a glacier and adds braking knots evenly to the length of the rope as seen in this answer. The person leading the rope falls into a crevasse and the knots do not stop the fall.

How does the rest of the team pull the leader out given that the knots would jam up the system?

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    You'll need to use your other rope at that point. You did bring it, right? – Toby Speight Feb 15 at 17:43
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    @TobySpeight, yep, the leader has it in... his... pack. Oh. – Wossname Feb 15 at 18:38
up vote 18 down vote accepted

In a 3:1 (Z-pulley) haul, the victim's rope is used for hauling directly. As you point out correctly, a surface rescue is impossible if you have knots in the rope, since the rope is under tension and you cannot untie the knots.

However, you can also drop a different strand of rope down to the victim and haul them out with that (it's then called a rescue strand). Since it's not under tension, it's possible to remove all knots from the rope before sending it down.

Some examples are a 2:1 (C-pulley or drop loop) haul or a 6:1 (C cross Z) haul, where in both cases you drop a bight of rope down to the victim. They attach the rope (with a pulley) to their harness, and then the rescuers haul. You could also send down a single strand of rope down and do a 3:1.

In any case, for a surface rescue, you need some rope available on the surface. All climbers tied together on a glacier should have some additional rope to perform a rescue.

Do note that all these require the victim to be conscious and able to help. If this is not the case, a rescuer needs to rappel into the crevasse, potentially address any immediate life-threatening injuries, clip the rope to the victim, ascend back out, then haul. This gets quite complicated, but is part of the guides' exam.

The last option would be for the victim to self-rescue, passing their prussiks over each knot in the rope. Clipping into the knots is possible and makes life a little bit easier.

  • 1
    Very satisfying answer thanks – ldgorman Feb 15 at 15:14
  • Both of these suggestions require the victim's active involvement. If the victim has been incapacitated, is he or she gone? – Solomonoff's Secret Feb 15 at 20:18
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    A rescuer can rappel into the crevasse to attach a line to the victim. There is video footage of PGHM doing this. – ldgorman Feb 16 at 7:54
  • @Solomonoff'sSecret thanks for the comment, I added a few lines regarding what to do with an unconscious victim. – Felix Feb 16 at 8:41

In addition to Felix's excellent answer of what should be done it practice, it is well worth knowing how to pass a knot in the rope (whether while rappelling or hauling). This will generally be more time consuming than just having an extra length of rope for which to affect the rescue and it should be noted that the knots that were tied to add friction on the lip of the crevasse during the fall will also add friction during the haul back out, perhaps becoming completely jammed up on the lip.

As this is a standard self-rescue technique, I'll give a brief overview of how this might look for a typical 3:1 z-drag setup. The additional gear requirements are minimal, needing only an extra sling/prusik and two carabiners.

Always obtain professional instruction

  1. Rig the z-drag as normal, but with one key difference: attach the braking prusik to the anchor with a load-releasable knot, e.g., a Munter-Mule hitch.
  2. Haul as normal until the knot in the rope gets close to the anchor. Clip a backup knot, untie the hauling prusik and retie it on the other side of the knot in the rope.
  3. Haul until the knot in the rope is jammed up against the braking prusik.
  4. Use the extra sling to tie another prusik onto the hauling line below the knot to act as the new braking prusik and clip into the anchor (if there will be more knots to pass, make sure to use another Munter-Mule). Slide this prusik as far as possible down the rope.
  5. Making sure a backup knot is tied, slowly release the Munter-Mule on the original braking prusik until the load is safely taken up by the newly tied prusik. Remove the original prusik from the system completely.
  6. Haul another foot or so until the knot in the rope is up against the pulley or carabiner at the anchor. Either untie the knot (generally difficult, but simpler) or slightly extend the attachment point so that the pulley/carabiner can be reattached below the knot in the rope.
  7. Repeat this process until the fallen climber is safe.

For variation on this approach, see the following technical bulletin from Petzl: Crevasse Hauling on a Rope with Knots. While illustrated with a Micro-traxion and a tibloc, the same procedure works with prusiks as well.

It proceeds much in the same manner for steps 1 and 2, but then uses an extra sling to connect the hauling prusik to the anchor (shown in green):

Petzl Tech Bulletin

Pull on the hauling system to release tension on the braking mechanism (whether micro-traxion or prusik), and then allow the rope to slide back through the system until the weight of the climber is taken up by the green sling. With this newly introduced slack, untie the knot (or pass it by extending the pulley at the anchor), then haul again until the green sling is slack and can be removed.

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    As an interesting aside, it was ultimately being unable to rappel past a knot that killed Tony Kuntz on the eiger. He was about 10' from rescue but couldn't undo a knot because of his frost bitten hands. Not the same subject I know but your post reminded me of this – Liam Feb 16 at 8:57
  • @Liam Absolutely. The story of Toni Kurz is one of the most tragic episodes in alpinism, up there with the first ascent of the Matterhorn. The German film Nordwand (North Face) is one of the most realistic climbing movies I've ever seen (insofar as what goes into pushing the limits of alpinism). – erfink Feb 17 at 2:49
  • Yeah, I've seen it, very good – Liam Feb 19 at 9:05

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