Retrieve ice-screw after descending

Suppose for climbing/rappeling down the team uses ice screws to make the base. Obviously the screw will need to be recovered after everyone has gotten down.

We were taught and shown (and I have forgotten, hence the question) a nice technique to tie a cord to the ice screw and let it rotate around the screw as it (the screw) was being driven into the ice. Then tugging on this cord from below would unscrew the piton from the ice. Basically this would allow the climbers to retrieve the ice screw after the last person got down.

Of course, using a V thread to make the base to rappel down circumvents this problem. But I would be happy to see a video or read a short description of how to recover the ice screw.

There is a video, unfortunately in German, but the steps are pretty well visible. However, be warned that this technique is not without risk:

• You are only using the front part of the ice screw which increases the risk of the screw breaking out. Add an unweighted redundancy for the first people abseiling of this construction
• The quickdraw could slide over the ice screw top. Ensure it is suffiently pointing upwards
• The screw might accidentially unscrew. When abseiling make sure that both strands of the rope are fed through the device at the same speed
• When unscrewing, you get a sharp pointy screw falling down 30 to 50 meters
• Thanks for the video. I knew it was simple, but not having done it in the past few months, couldn't recall the steps. Agree on the risks. But I think some of it can be mitigated. Using a thin cord and making the later loops on top of the older ones (as also shown in that video 1:20 - 1:35) will cost only about 1-1.5 cm length of the piton. Jan 10, 2022 at 17:29
• Would it not be better to use just one strand of the rope to descend on? The other strand will be prevented from passing through the QD by a large knot/carabiner. A thin cord goes straight down from the looped cord and will be pulled to retrieve the screw. And we also have the full length of the main rope to abseil down on. Then there would be no risk of accidental unscrewing because of not feeding both strands of the rope at the same speed. Jan 10, 2022 at 17:30
• Also, what is the advantage of placing the QD over the screw itself, instead of passing it through the handle? Jan 10, 2022 at 17:41
• If you place the quickdraw at the hanger of the ice screw it will create a high leverage. Remember, the ice screw cannot be inserted completely due to all the cord. It is recommended to attach any load as close to the wall as possible, just as one would tie off a piton that does fully go in. Jan 11, 2022 at 11:43
• Regarding using only one strand of the rope and a cordelette to retrieve it, yes this could be done, but you need to make sure that the not does not slip through the carabiner. However, in ice climbing the use of double ropes is standard (all those sharp pointy things...) so normally you can use the full length of the rope anyway Jan 11, 2022 at 11:44

It's pretty simple.

• Place the screw, finishing with the hanger upwards (as the rope will just be hooked over it). Back it up with any reasonable anchor, with a small amount of slack so you can tell whether it gets loaded.
• Attach your retrieval cord to the screw, and wrap it anticlockwise around the screw enough times that pulling it will completely unscrew it.
• Place the doubled rope over the screw, making sure that it doesn't lift off.
• Attach the free end of the cord to the left side of your doubled rope with a loop or perhaps a prusik knot. Make sure you identify the end of this side at the bottom - e.g. with an extra knot.
• All but one of the party now abseil down this doubled rope, being careful to feed the ropes through together, with no differential.
• Just before the last person descends, remove the backup. (If the screw moved and the backup is loaded, treat that as a warning, and sacrifice the gear!)
• After abseiling, separate the ends as normal, then pull the end you identified as being the left end. This will now pull the cord to unwind the screw. Keep clear of the falling rope that has a screw attached.
• Thank you for detailing the steps. I accepted the other answer because it linked to a video which is easier to understand for these things. Jan 10, 2022 at 17:37