Under what circumstances would you not use a recently planted ice screw?
I've done a lot of bouldering, sport climbing and some aiding. Awhile back I went ice climbing with some guys for about a week. I didn't participate much simply because I didn't feel the confidence I normally do in the equipment. Particularly ice screws.
I asked the question, "Under what circumstances would you abandon a screw you just placed?" I did not get total consensus on the circumstances that would need to be present in order for a screw to be abandoned for use. The discussion became so heated I abandoned it completely.
Answered I received:
When there is a long vertical crack that is formed when placing it.
When a short horizontal crack is formed during placement.
When a star crack created when placing it.
I will say that a star fracture did receive some consensus among the crew. A few of these guys have been climbing for a long time and their practices seemed safe but none of them had any physics degrees either, not that I do.
My question, as above is, under what circumstances would you abandon a recently placed ice screw?
As well, how far away from the crack would you have to go to place the next one safely?
This post was sourced from https://outdoors.stackexchange.com/q/10427. It is licensed under CC BY-SA 3.0.
1 answer
I will only focus on signs to assess the quality of a placed ice screw. There are many factors that influence the outcome like the location, temperature, ... but they deserve an answer of their own.
The most important thing is, that the screw is placed all the way in solid ice. On the surface you can judge this easily. The deeper parts are assessed by what comes out of the hollow inside of the screw while "drilling". Ideally this is a compact column of ice that breaks off in one ore several big pieces. Usually though the ice will break off quickly after leaving the screw. This is still ok. The NoGos are:
No ice comes out of the screw will drilling.
This means that you drilled into air. This can occur during formation of the ice or due to melting processes which can produce completely hollow ice columns (though you should not climb on such in the first place).The ice (more like snow) "trickles" out of the screw.
In this case you drilled into snow or ice with lots of tiny air bubbles.
In both cases the screw placement will be severely weakend and you need to replace it. How far away you try again depends entirely on the situation. Try the closest place that is in some way distinct from the orginal one.
If the above is fine the screw is most likely fine. Unless you placed your screw on top of a bulge, which is anyway a bad idea, small cracks at the entrance point are no big issue. I only ever saw such in really deep temperatures (below -5degC). Of course if you have multiple or very long cracks, thats not good. However that should not happen as drilling an ice screw does not displace lots of ice, it cuts, so there is no reason for cracks to form. This is much more likely when hitting your axes into the ice, so you will notice it there first. It can happen in cold temperatures after a big temperature rise or fall that the ice is both very hard and has tension on it. In this case you should not be climbing at all.
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