Continue with onX Maps
Sign in with Facebook
ice climbing anchors and safety of follower/team
|
hey all, i'm a rock climber starting to get into ice climbing, and trying to wrap my head around the safety aspects of it. as i was learning to trad climb, i followed many multi-pitch routes in the gunks, and i always felt secure knowing that the anchor that i was attached to was bomber, and we weren't going to get pulled off the wall in the event of a leader fall. transitioning to ice, i've been reading through threads to and it seems like there are a notable amount of people who don't seem to trust ice screws. i'm wondering how concerned i should be about an ice anchor blowing during a leader fall on a multi-pitch climb. my question is - assuming good ice, how bomber do you consider an ice anchor with two screws? it seems like a lot of the multi-pitch routes near me are gullies, which i'd imagine lower the chance of the anchor blowing/increases chance of leader groundfall, but i'd love to hear perspectives on all types of routes. any recommendations on books for how to read/evaluate ice? thanks! kyle |
|
Hownot2 tested screws on YouTube although they tested in glacier ice which is exceptionally strong. Will gadd drills a v thread on YouTube and incrementally chips away at it and tries to break it free. Results may surprise you. Try it for yourself....you probably won’t have further worries |
How bomber? Pretty damn bomber. But not infallible. |
|
Assuming your leader is competent at placing screws, the big danger with multipitch ice anchors is falling ice from above. |
Kyle Turgeon wrote: It's curious to me that people don't trust gear (ice screws especially) when there are very easy ways to test the strength of a screw without leaving the ground in addition to videos of testing results with data. And to add to that, it's actually easier to assess the quality of an ice screw placement than rock gear as you have direct tactile and visual feedback the entire length of the screw as you place it. I guess it's probably a lingering thread from when climbers were using Salewa and Chouinard screws, Snargs, and conduit.. Obviously ice screw strength is dependent on the quality of the ice, which is (part of) why it's good practice to do a bunch of top-roping and learning to read ice prior to hopping on lead, as well as following around someone who knows what they're doing, but a good ice screw in good ice is plenty strong. There's a lot of very experienced ice climbers who will build anchors off one screw with a second as a back-up (similar to a vertical style bolted anchor) rather than going for a perfectly equalized anchor. Again, context dependent and you can nit-pick minutia and argue appropriateness in various situations, but the overarching point is that ice screws are really freaking strong. And to address another part of the OP post: a leader fall while ice climbing is bad and should be avoided at just about all costs for reasons entirely separate from fears of exploding an anchor. Usually people are more concerned about exploding their ankles, tib/fib, hips, back, lungs, shoulders, head, basically their whole body, in the rare case of a leader fall on ice. If someone is taking a lead fall on ice AND you're worried about the anchor exploding, you're in a bad spot. TL,DR: Ice screws are wicked strong, lead falls on ice are wicked bad |
Matt Z wrote: This is all you need to know right here!! |
Kyle Turgeon wrote: I'm going to say that book/video learning isn't really going to get you very far here, you learn to evaluate ice by climbing it and putting screws in, the feel of the screw turning and the core coming out of the screw will give you far more information about the placement than any theoretical "rules" in good ice a two screw anchor is as good as any gear anchor, and I'd argue, actually easier to evaluate, so probably more bomber than a lot of peoples trad anchors... key words being "in good ice" sometimes you just aren't getting optimal, again, time and lots of screws placed to make the judgment call of if it is good enough, sometimes you can add a thread or a driven tool, lots of tricks, but again, it's a time and experience thing to evaluate what you need to do to make things bomber. That said, if you are really planning your anchor for a leader to factor two onto it you should be bailing, if you don't have the physical ability to solo the pitch you have no business being on lead on an ice climb IMO, mental ability is different, it's fine to need the gear to convince yourself it will be ok but on a physical level failure is not an option. |
|
It’s all been said above. Any worry about ice anchors is totally unfounded. That’s useless worry space in your head. In general, your broken bones absorb a good chunk of the energy before you even weight a screw. Worry about your fitness and technique to keep you off the screws. The worry about falling in ice climbing has nothing to do with lack of faith in the pro - it’ll hold (caveat being generally climbs of grade 5 or below. WI5+ and above can start to get sketchier and sketchier due to the ice itself more than holding power of the screw). The worry is the potential injuries before you get caught. They’re more to protect you from death, not injury. TL:DR - By the time you’re climbing north of WI5+ you won’t care about screws, and below WI 5 you don’t need to care about screws. |
|
Keep in mind of course that ice screws are only as good as the ice they are placed in. |
|
2007 research paper on strength of ice screws under dynamic loading: Very short, slightly rough version: the mean force held by screws that successfully arrested various falls between FF1 and FF2 of 78kg mass was ~8.6 kN (11). Impact forces >10kN are more than likely to cause a screw to fail (13). Some stubby screws withstood 15kN (12). Ability to choose screw placement is an important factor (12). |
|
generally speaking modern screws in good ice are truck. You don't always find good ice. sometimes the sun starts melting your belay out and you have to pack snow on top of the screws and sometimes even move them to a different spot half way thorough the leaders pitch.. other times the ice is wicked cold , brittle and full of air pockets.. It takes awhile to learn all the tricks and it ain't for everyone. |
|
Ice is brittle, especially cold ice or ice that is loaded quickly (high fall factor fall that are close to the belay on multi-pitch climbs). That means that every once in a while, you'll be surprised by how weak an ice screw placement is. The data cited in the mra.org/wp-content/uploads/… shows this. The standard deviation is on the order of 1/3 of the average. So ~2% of those ice screws are predicted to fail at less than 3.5 kN, which would be the daintiest of leader plops; something like 1 time in a 1000 the ice won't hold body weight. (Trick question: If you fall on a 1000 of those ice screw placements, what are the chances that 1 will fail on you?) For comparison, lots of "three sigma" carabiners would be happy holding 20 times body weight in that 1 in a 1000 fall event. Before the vast number of Weibull distribution loving Mountain Project readers get angry, I recognize that applying gaussian statistics to brittle material failure is suspect, but it doesn't change the situation: sometimes the ice is a lot weaker than anyone wants to acknowledge. I have yet to see any data set with a standard deviation that makes me think all my ice screws are bomber. And yet to see a data set of ice screw failure loads that would be big enough for Weibull analysis. And I call baloney on anyone's anecdotal data set along the lines of "I've fallen lots of times on 13 cm screws and none failed so they are all bomber." Every once in a while, there is an accident where the ice belay anchor fails. I remember one that happened about a decade ago in Valdez; I think it's written up in the AiNAM, but I can't find it quickly. Two ice failures--not belay anchor--that did appear easily via google: |
|
Dave, minus all the big words you are absolutely correct. Ice screws are truck in good ice but they are often not in good ice... many times I am aware that I am basicly soloing trailing a rope for my partner. that is one of the reasons that I do so much soloing. Its a tool that I have on my rack. If I get halfway up a pillar and the ice becomes so candled or aerated etc. that screws would be a waste of energy because they would be so weak I know how far and hard i can go without really needing a screw. If I can see good ice within my soloing ability I can keep climbing. If not I need to downclimb to the last good ice and bail. Either way my soloing abilities will keep me alive. |
|
Basically it’s the same as leading trad rock. The pro is only as good as the person placing it. Just like trad placements, there’s a whole lot of “depends” and beyond meaningful statistics that would make any difference on Your particular lead. Roughly, a decent screw is about the same as a decent stopper That said, the Attaway paper linked earlier made some potentially significant errors in their ice density analysis. For those so inclined to draw any meaningful statistical conclusions from holding data, any screw placement should likely be normalized to the density of the screws displaced core.(per screw tube volume) This gives a more realistic measure of the quality of the ice placement. |
|
Indeed, lots of "it depends." Ice density will be complicated. A "honeycomb" of air bubbles or other non-ice elements might well prevent brittle crack propagation; or leave too little material for structural integrity. You can get a sense of this from how ice cracks as you place screws--especially 30+ year old ice screws that stress the ice so much more than modern ice screws. As an aside, rock is relatively impervious to changes in load rate and might even sometimes be stronger at higher load rates. Thus, protecting the belay is more important when (multi-pitch) ice climbing. |
|
Jimmy. Not sure you understand me. . When the ice is good the gear is good. When the ice is shit the gear is shit. If you do a lot of soloing then you do stand a better chance of keeping your shit together when it goes to shit. You also know what shit works and what doesn't. I don't take chances soloing or leading. Keep your shit wired tight at all times. |
|
Ice is brittle. Even good ice is brittle*. Its failure behavior is fundamentally different from that of rock or climbing gear. Glass has a higher compressive strength than aluminum, but funny thing, there are no glass chocks or cams. How would your rock climbing habits change if your chocks and cam lobes were made out of glass? Consider adopting those habits in your ice climbing. * More on how tough ice is and how its toughness are affected by temperature and load rate: cambridge.org/core/journals… A handy table of fracture toughnesses, including ice, glass, aluminum, & steel; an additional material of interest to climbers, nylon, has fracture toughness is about 3 in the same units: semanticscholar.org/paper/T… |
dave custer wrote: FYI, your link is broken. Here is the right link: mra.org/wp-content/uploads/… This testing was done using only 12-13 cm screws, so it may not be the best data to apply to anchors. More importantly, the failure that had the lowest strength (<4 kN) out of a very small data set (11 samples) was placed in poor ice that the author believed, at the time of placement, was "phycological protection only." Here is an excerpt from page 11 of the paper:
It doesn't make any sense to statistically extrapolate these findings to your own anchors, unless you make a habit of regularly placing short screws into poor ice at anchor stances. Simply removing that one outlier datapoint significantly changes the stdev of the data and also pushes the average up, meaningfully changing the 3-sigma points, and changing your "2%" and "1 in 1000" numbers by an order of magnitude. Also, since anchors have 2 pieces, you need to have 2 screws fail, not 1, so the odds likely get significantly better than predicted by (mis)-applied statistics. The generalization that we should be trying really, really hard not to fall on screws still holds true. The only issue I take is with trying to present extrapolations from this data as a scientific exercise, which it isn't. |
|
^Holy cow, Kyle and I agree! Let’s see if it can continue… On the density issue. At least the way I read it, The paper made erroneous conclusions based on flawed procedure. Let’s set aside issues of “micro-density” (micro air bubbles “dissolved” in otherwise uniform ice) and agree that “macro-density” is important— the ratio of solid ice to air pockets in less uniform ice. This can be intuitively understood that a bigger more consistent ice core coming out of your screw is better than a faltering, smaller amount. My suggestion is that any Future quantitative tests should capture and reference this core density as a factor. It really is the only realistic way of trying to compare “apples to apples” in terms of the quality of a placement. |
Kyle Turgeon wrote: Don’t fall while ice climbing. |
|
I saw a terribly inexperienced leader take a 15 footer onto her second screw - a 19cm BD turbo express screw placed in super soft mush ice - and it kept her off the deck. The whole situation had just about all you could have go wrong - falling on ice, bad placement, high fall force relative to the amount of rope in the system, etc and it worked out. I became much less worried about an ice screw holding a fall after seeing that. Anecdotally, I've also started to run into more people who have broken rule #1, and I have yet to hear of a screw pulling in any of those incidents. |
