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      WELCOME TO THE CASCADECLIMBERS.COM FORUMS   11/10/22

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primate

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Posts posted by primate


  1. On 4/17/2018 at 3:00 PM, G-spotter said:

    When you say "quantitative estimates" you mean "make up some numbers and pretend that you've switched from qualitative to quantitative analysis" right? Not actual measurements that would really be quantitative analysis?

    Yes, when I write 'estimate' I mean that I make the number up (I don't read them off my handy risk-o-meter). But I try to do it in an honest fashion. Seriously, though, I think quantitative reasoning can be useful even in the absence of authoritative data.


  2. 3 minutes ago, JayB said:

    Can you elaborate on some of the ways that you feel that framing your risk analysis in terms of equations helps you climb more safely? Not calling your claims into question here, just hoping to learn something that I might be able to put to use.

    I was specifically thinking of arguments like justifying exposing oneself to mountain hazards by the fact that the drive to the mountains has some risk. I've taken to skiing inbounds when there is significant avalanche danger, as an example. If I am realistic about the ability of the parties I ski in to judge and manage avalanche risk, skiing backcountry when there is significant possibility of initiating slides is above my risk tolerance threshold. I don't ski as much powder as I would get to otherwise. It is a lot easier for me, personally, to 'deny' myself if I have made some quantitative estimates. I'm not talking about doing detailed calculations on route, I'm talking about changing my goals in such a way that my wife has a higher probability of having me to grow old with. If I just trusted my gut, and not some numbers, my gut would find a way to tell me that I could do whatever it was that I wanted to do.


  3. This is a great thread; one of the best things I've read on cc.com in a long time. I'm very sorry to hear about Marc and Ryan. I think it's a social problem that some find discussing risk to be disrespectful of their memories.

    On a lighter note, I'm a little dismayed that so many on here express the belief that risk is not quantifiable and that equations are inherently useless for informing our decisions. I think it is extremely worthwhile to look at risk estimates, which, of course, are limited in what they can say by the availability of data. I would urge folks to think about what they get out of climbing and maybe look for behavior modifications that can improve the safety of the climbing w/o sacrificing the positive aspects. Equations are definitely useful for evaluating different climbing practices. The main concepts that are needed to estimate how probabilities accumulate are 1) the probability for A and B to both occur is the product of their individual probabilities and 2) the probability that (at least one of) A or B happens is the probability that A happens plus the probability that B happens minus the probability that both A and B happen. Naively one might think that if you expose yourself to a 1% probability of dying 200 times the total probability of dying would by 200%. It's actually less than 100% because you must subtract the probabilities that you die more than once in the 200 attempts. That's why @Bronco's suggestion above focus on the probability of not dying gives a simpler expression: the event whose probability you're estimating is not dying on the first climb AND not dying on the second climb AND ... not dying on the nth climb, so the total probability is just the product pxp...xp=p^n if p is the (assumed identical) probability of dying on each climb. If you try to construct the probability as the probability of dying on the first climb OR dying on the second climb ... OR dying on the nth climb you need to remove events where you die on more than one climb.


  4. Fishscales will not climb like skins. But for rolling terrain, not having to deploy and remove skins is a great advantage. And you can always slap skins over the scales for sustained, steep climbs. I've never put AT bindings on fishscales but it has been discussed extensively at telemarktips.

     

    Do it! And tell us how it worked out.


  5. What makes the wilderness we have valuable? Basically, it is the absence of roads. If we close more roads, we will have more roadless areas. The roadless areas we have will be 'deeper' and (from my POV) more valuable. I understand that many do not share this view--their viewpoint is as important as mine and as a society occupying this land we should try and find a consensus solution. For me the question is 'how much roadless land do we want to leave future generations?'. It's my beleif that almost everybody (and certainly society as a whole) 'wins' when we preserve land. Hell, we can always build roads all over it later!


  6. Fern, that's not how glaciers grind down mountains. Stones and grit get embedded in the ice and moves with it. THAT is what grinds down solid rock.

     

    I think modern science has found that most of the weathering action of glaciers is actually done by 'quarrying' -- large blocks are removed from the glacier bed and carried along by the glacier. The action of embedded rocks in the glacial ice does account for polish, striations, etc., but this action is not sufficient to remove material quickly enough to account for much of the total erosion accomplished by the glacier.


  7. I have the summer off and am looking for partners for scrambling on weekdays. I live in PDX area and am a beginner in decent shape. I have car and some gear. If you need a partner and don't mind a novice, I am always up for adventure.

     

    pm me or use the following:

    prange@pacificu.edu

    (530) 357 0996

     

    Micah


  8. I have a Cassin axe similar to the Dragonfly, but it has (I think) a steel head. The shaft may still be aluminum. I think the model name is "flash" or somthing like that. Maybe this axe is being confused with the dragonfly? I only use it on moderate snow, so I wouldn't know about it's durability for ice, but it seems pretty sturdy.


  9. quote:

    Originally uttered by some clueless asshole:
    "Ithink more to the point, we need to meet the minimum services the public isexpecting.

    WTF? The minimum sevice I expect from agencies managing our public land is to leave it alone so I (and hopefully people who come after me) can enjoy it in a natural (i.e. unlogged) state. I realize that some managment must be done to mitigate heavy use, but I think the best managment policy is often to let the land heal itself. Ironically, this is also a very cheap plan, so USFS shouldn't have to charge me much.


  10. My Mt. Adams Wilderness Map claims that Mt. Adams has the largest volume of the cascade volcanoes. I don't have the map with me, but I think they quote some figures the validity of which I have no idea. I think the map said that Shasta was 2nd and Ranier was 3rd. I'm still perplexed about the issue of deciding which volume to count as part of the mnt. and which the surroundings.


  11. We are planning to ski to summit in two days from Smith Butte. We thought it would be nice if we could get our packs hauled part way, maybe to South Butte. I don't know much about the area or snowmobiles, so I'm not really sure what is feasible--I just thought I would ask, becuase I think the skiing will be a lot more fun with light packs. You can send me a pm or email me at prange@pacificu.edu.

    Thanks.


  12. Yes. There are a couple of big parking lots and a big warming hut with a stove that is always teeming with snowmobilers and thier kids at the snowpark. The lots usually get plowed in the morning after it snows, but if it snows down low it takes them a while to get around to plowing the snow parks.


  13. Fern:

    I think the 12 in your formula should be a 4. If you assume the hole you dig is a cylinder of height h and diameter h, then the horizontal cross-sectional area is <pi>(h/2)^2 and the volume of the hole is V=<pi>(h/2)^2*h=<pi>(h^3)/4. This implies that h=(4V/<pi&gt wink.gif" border="0 ^(1/3), so to estimate the depth of a hole from the volume, you would take V, multiply by 4, divide by pi, and take the cube root of the result. This would give you the depth of a cylindrical hole of volume V with height equal to diameter. Perhaps you used a different assumption?


  14. Fern:

    I think the 12 in your formula should be a 4. If you assume the hole you dig is a cylinder of height h and diameter h, then the horizontal cross-sectional area is pi*(h/2)^2 and the volume of the hole is V=pi*(h/2)^2*h=pi*(h^3)/4. This implies that h=(4V/pi) ^(1/3), so to estimate the depth of a hole from the volume, you would take V, multiply by 4, divide by pi, and take the cube root of the result. This would give you the depth of a cylindrical hole of volume V with height equal to diameter. Perhaps you used a different assumption? smile.gif" border="0

    [ 12-07-2001: Message edited by: primate ]

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