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Author Topic: Saturday February 22, 2014 Chair Peak Avalanche  (Read 107065 times)
Jim Oker
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #75 on: 02/27/14, 01:44 PM »

Shanski posted in the spirit of generating a healthy conversation. Again, thanks for doing so! In that spirit, I want to ask about this phrase from one of CookieMonster's posts:
Quote
...appropriate terrain that included a generous margin of safety...
What do folks think about this as a generally stated goal for the sort of terrain you'd want to be on this past weekend? Right on? Too much caution for you personally with the inclusion of the notion of "generous margin of safety?"

And how well do you think this particular route choice met this goal?
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BillK
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #76 on: 02/27/14, 02:00 PM »

I think the statement is right on for that weekend, and the "generous" statement fits given the uncertainty.  As is evident from my other posts, I think the route choice comes nowhere near that.
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Good2Go
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #77 on: 02/27/14, 02:17 PM »

Very good post, very constructive. The points made about experience level are very sobering, and reminded me of this paper put out in 2000 by Ian McCammon. This quote out of the summary is worth considering.

"Avalanche training did not appear to decrease the hazards
that groups exposed themselves to, and in the case of vic -
tims with basic training, hazard exposure actually
increased."


McCammon 2000

Totally disagree. Cookie is miscasting the OP's basis for including their reasoning for being in that spot at that time in the TR, and even worse, describing it as "low skill".  And his tone is condescending.  If one of the best avy experts in world Ruedi Beglinger can't accurately predict the danger of a deeply buried instability, then certainly none of the folks on this string can either.  If the OP's group had skied the crap out of that line all day without incident, wouldn't it have been "higher skill" (i..e, a better understanding of the situation than NWAC and the experts on this string)?  If not, why? Isn't the whole purpose of avy education and NWAC forecasts to help inform us when it's safe to go?  If not, then why not just ignore it and ski 20 degree trees for the rest of your life?   (Seriously.)

BTW - All you wannabe experts, can I go ski that same slope right now, what with the "moderate" NWAC forecast and all, or should I still superimpose your higher level of skill to that guidance and stay clear?  (Not seriously.)
  
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BillK
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #78 on: 02/27/14, 02:25 PM »

Go ski it....me, I would still wait a bit, and it would depend on recent weather conditions, time of day, etc.

I wonder what Ruedi would say he learned from that horrible accident.....poor bastard probably eats, sleeps and breathes it everyday of his life. 
« Last Edit: 02/27/14, 02:46 PM by BillK » Logged
snowdog
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #79 on: 02/27/14, 02:31 PM »

Thought I would add to this since I was the one who posted the Slot trip report and I just saw this long series of comments.

First, i'm sure glad the three of you were not injuried and made it back safely.

Second, kudos for writing such an excellent report and to all others who have commented to make this an important lesson for all of us.

As to conditions in the Slot and why we decided to ski it, our thoughts, right or wrong, were that it would probably be okay for the following reasons:

In spite of the heavy recent snow, the slot sluffs off snow quite frequently because of it's rather steep slope.

It is also skied very frequently all year long, unlike the north side of chair peak.  This frequent skiing compacts the snow in the slot similar to a lift ski area and because it is narrow, most of the slot gets compacted.  At the same time, this frequent skiing brings down a lot of the loose surface snow.

And since it is so protected, wind loading shouldn't be an issue in there.

In addition, someone had just skied the slot, solo, before us.  we actually thought this was rather risky to be heading up there alone on such a day.

We also noticed very stable conditions in the upper surfaces as noted by many people.  What we didn't properly assess was the deep instability that existed.  however, with all the skiing in the slot, does this still exist there?  Without digging a deep pit we won't know.

The area where we knew we were treading lightly was getting to the Slot after coming out of the trees.  We kept a fair distance from each other but we were discussing it as we skinned up.  No question, this is the area that made us most nervous and we almost turned back.

Just trying to add to the conversation as to why we chose to ski the slot.  Maybe we got lucky, maybe it was stable because of the reasons i noted.

However, from all the excellent comments made by others, I will choose more wisely in the future.
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aaron_wright
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #80 on: 02/27/14, 03:35 PM »

I don't know if I've ever heard Ruedi described as "one of the best avalanche experts in the world".  I don't think anyone here has claimed to be an expert, most, including myself, realize we aren't so would exercise a bit more self discipline and restraint. A lot of the folks posting here likely have decades more experience than the OP. Even if the NWAC completely omitted and mention of PWLs and deep slab instability, they  certainly mentioned wind and storm slabs on high ridgelines which is what caught this group.

You seem to have some personal investment with this topic given your emotional and somewhat irrational responses.

Totally disagree. Cookie is miscasting the OP's basis for including their reasoning for being in that spot at that time in the TR, and even worse, describing it as "low skill".  And his tone is condescending.  If one of the best avy experts in world Ruedi Beglinger can't accurately predict the danger of a deeply buried instability, then certainly none of the folks on this string can either.  If the OP's group had skied the crap out of that line all day without incident, wouldn't it have been "higher skill" (i..e, a better understanding of the situation than NWAC and the experts on this string)?  If not, why? Isn't the whole purpose of avy education and NWAC forecasts to help inform us when it's safe to go?  If not, then why not just ignore it and ski 20 degree trees for the rest of your life?   (Seriously.)

BTW - All you wannabe experts, can I go ski that same slope right now, what with the "moderate" NWAC forecast and all, or should I still superimpose your higher level of skill to that guidance and stay clear?  (Not seriously.)
  
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RonL
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #81 on: 02/27/14, 03:52 PM »

Thanks for chiming in on your reasons for skiing the slot. I agree that exiting the treelike is where the first bit of concern would be for me on that route in these conditions but I would also have had reservations about the exit after skiing the slot.

I wonder if persistent weak layer is the right term for the slide we are talking about. In my mind it was all one big storm system and rather than looking at it differently from a trickier continental snowpack mindset I just viewed it all as a big dump that although settling enough to make trail breaking easier as time went on was far from bonded or bridged. I think labeling this as pwl is lending to much mystery to it rather than in terms of our normal multi foot storms where one expects natural releases and knows to use caution. I don't have the official definition memorized but I would tend to reserve pwl for something that lasted more than a storm.
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jj
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #82 on: 02/27/14, 04:02 PM »

Cookie's comment that the party was "most certainly not following best practises at all," seems completely out of line.  In fact they did many things right: pre-trip research, equipped with appropriate gear, discussion of the conditions, safe travel in avalanche country, transitioning in a protected area.  In fact, the decision to transition on an intentionally chosen terrain island was likely what prevented injury.  I shudder to think that most of the terrain islands I choose wouldn't come anywhere close to protecting me from a slide with a 10 foot crown running more than a thousand feet.

The only major error I can see (and only in retrospect) was incorrect evaluation of the deep layer risk on the terrain they chose to travel on.  As many have mentioned evaluating deep persistent layers is challenging even for well trained backcountry travelers.  This will certainly be a recurring topic over the coming weeks.  Is the deep persistent layer "safe" now?  If not, when will it be?  Those answers will be different for everyone and depend on little more than individual risk tolerance.
« Last Edit: 02/27/14, 04:12 PM by jj » Logged
kerwinl
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #83 on: 02/27/14, 04:06 PM »

Totally disagree. Cookie is miscasting the OP's basis for including their reasoning for being in that spot at that time in the TR, and even worse, describing it as "low skill".  And his tone is condescending.  If one of the best avy experts in world Ruedi Beglinger can't accurately predict the danger of a deeply buried instability, then certainly none of the folks on this string can either.  If the OP's group had skied the crap out of that line all day without incident, wouldn't it have been "higher skill" (i..e, a better understanding of the situation than NWAC and the experts on this string)?  If not, why? Isn't the whole purpose of avy education and NWAC forecasts to help inform us when it's safe to go?  If not, then why not just ignore it and ski 20 degree trees for the rest of your life?   (Seriously.)

BTW - All you wannabe experts, can I go ski that same slope right now, what with the "moderate" NWAC forecast and all, or should I still superimpose your higher level of skill to that guidance and stay clear?  (Not seriously.)
  
-Nobody claimed to be able to predict the danger of the PWL, that is point multiple people have made. A persistent weak layer is fickle enough, that even those with many hours/days of dealing with such layers have an inability to predict behavior with any accuracy.
-If the OP's group had skied the slope several times without incident it does not mean that they would have had "higher skill". Exposing yourself to very small probability of a catastrophic event over time will lead towards harm/death over repeated exposure, no matter how "skilled" the party is. Experts get killed in the same avalanches that kill novices, it is not a matter of skill, it is a matter of taking a chance.
-The purpose of education/nwac forecast is to help inform us of the current situation, but it is only a start. The forecast or our training can never tell us that it is safe travel any slope, it is merely a starting point to be followed by good decision making in the field.
-There is an assumption in that people with high levels of expertise are more conservative, then those with low levels of skills, which is not true, as evidenced by the paper I linked earlier. Some people myself included without years and years of experience simply choose not to take chances and ski in areas that have catastrophic consequences if an event occurs, I would not conflate that risk aversion to high skill.
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Good2Go
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #84 on: 02/27/14, 04:13 PM »

I don't know if I've ever heard Ruedi described as "one of the best avalanche experts in the world".  I don't think anyone here has claimed to be an expert, most, including myself, realize we aren't so would exercise a bit more self discipline and restraint. A lot of the folks posting here likely have decades more experience than the OP. Even if the NWAC completely omitted and mention of PWLs and deep slab instability, they  certainly mentioned wind and storm slabs on high ridgelines which is what caught this group.

You seem to have some personal investment with this topic given your emotional and somewhat irrational responses.


Emotional? irrational? I got a good laugh out of that, thanks.  As much as I'd like to engage in a personal battle with you Aaron, I don't have any skin in this game. I just think it's counterproductive to pontificate and condescend when somebody is retelling a story about a mistakes in judgment, especially when they thought they were following "best practices".  You (and Cookie and the rest) could have made your point by simply saying that when there's enough uncertainty, you choose to ski in conservative spots. Anybody reading this string would have then clearly understood your point (and received the benefits of your "wisdom").  Instead, you chose to critique the OP's choices as though he was saying he would do it all the same way again, when what he was actually saying (IMO) is that those choices were insufficient under the circumstances, and lead him to the wrong conclusions. Now, instead of attacking me, how about you turn your venom on that guy who posted about skiing the Slot?  He seemed insufficiently recalcitrant by TAY standards, don't you think?
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Micah
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #85 on: 02/27/14, 04:28 PM »

Thanks for your perspective, snowdog. As others have said, this thread is of great value IMO. I encourage the OP to respond; I hope he/she feels comfortable coming back.

We should be cautious working backward from accident narratives to criticism.

I wanted to add my voice to those empathizing with the OP. I heartily agree with many of the critiques, but I think some of the criticisms have been delivered with some condescension. This may have been in response to perceived hubris in the original post. I think it was not hubris but defensiveness, and I would encourage the community to read the trip report generously, taking into account the awkwardness and difficulty of recounting a trip in which your party was caught in a large avalanche. I would like to think I would not find myself caught in a slide such as this one, but it only takes one misjudgment or lapse of vigilance to find yourself in a bad spot. So please take my ramblings below as constructive (they are intended to be so).

I think this party missed the forest for the trees, and I wonder if this is not a danger of avalanche education. Lots of information was considered (NWAC, reports from the guide friend, the party's own observations on the trip, etc.). But for this hazard all the relevant information is contained in the observation that a shitload of snow had fallen continuously over the preceding two weeks. A simple rule of "don't ski over 30° within a week of a big storm" would have been worth more than your L2 avalanche class. Or, to say it another way, sometimes the inspection of a variety of data leads us to underestimate the uncertainty in our final evaluations.

I often hear things like 'your snow assessment should not be used to provide evidence of stability only evidence of instability.' While I appreciate the sentiment, I think this is an operationally meaningless statement -- the absence of evidence of (serious) instability will yield a decision ski just as evidence of stability would have.
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watsonskipsmith
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #86 on: 02/27/14, 05:46 PM »

I would like to thank Shawnskis for his very brave, very important, most excellent and valuable post.

I do not have alot to add to "the meat" of this thread, but can offer some personal experience in regards to *Guide is pronounced "guide", not "god."
I was instructed by an experienced Canadian Mountain Ski guide to "follow my traverse and ski right of the tracks"
Well I did just that and triggered a slab with 3-4 foot crown which ran down the designated ski run and  knocked over another client below (no one hurt, but they did infer that I was to blame in the hut debriefing afterward. The CMS guides are awesomly good, it was a rare event)   

A second thought sticks out in my digestion of the thread-
I was very impressed by, and wanted to re post the quote from the special BC avi statement-

"Wait. Wait longer than usual before moving onto larger, more aggressive terrain. Some runs might have to wait for a couple of weeks or more. Some might be out for the rest of the season. This is especially important for all you folks in the coastal ranges where you’re used to waiting a few days to let things settle down, then going for it. The snowpack you’ve got out there, especially the south coast, is like nothing many of you have dealt with before. Don’t use your coastie tactics and expect them to work this season. You need to think more like the Interior or even the Rockies guys right now." 

A third maybe helpful thought, perhaps discussed here before?
The slot couloir part of the thread relates to what I refer to as the "TAY heuristic". Something I feel effects us all here at TAY.  TAY provides familiarity and we see posts from folks in all kinds of conditions which can perhaps lead us to a "those guys did it" thought pattern.

Anyway, kudos to all for a very thought provoking and mostly respectful thread.



« Last Edit: 02/27/14, 08:52 PM by watsonskipsmith » Logged
MW88888888
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #87 on: 02/27/14, 09:26 PM »

Close to a decade ago I wrote a TR on TAY about skiing Snoqualmie MT solo one morning, and created a nice flurry of internet fodder for the choices made re: avalanche safety, hydration and general incompetency.  I'm actually very impressed by the growth and depth of the responses here, generally.

Nothing much changes, yet everything changes.  Thanks for talking about your experience. I, too, have Tripped the White Fandango and am lucky to be alive.

Life is long, hopefully, and learning from it ensures its longevity.
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ski2fly
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #88 on: 02/28/14, 12:48 PM »

I think all of the conversation is interesting regarding evaluation, overestimating abilities etc.   The big variable here is we are simply not used to this continental type of persistent deep/weak layer here in this maritime climate.   All of the OPs original assessment and evaluations would apply on 9 out of 10 years and cover the spectrum of risks, but the threat of a catastrophic all-cuts-loose event was clearly not deemed a threat.   And at this point, it is so far down you can dig a 5 or 6' pit and not hit it. 
Would be an interesting study to have a core sampling tool to be able to extract a column of snow from the snowpack at various locations/elevations/exposures and see how variable that PDL is.
« Last Edit: 02/28/14, 12:53 PM by ski2fly » Logged
BillK
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #89 on: 02/28/14, 01:05 PM »

I wonder if persistent weak layer is the right term for the slide we are talking about. In my mind it was all one big storm system and rather than looking at it differently from a trickier continental snowpack mindset I just viewed it all as a big dump that although settling enough to make trail breaking easier as time went on was far from bonded or bridged. I think labeling this as pwl is lending to much mystery to it rather than in terms of our normal multi foot storms where one expects natural releases and knows to use caution. I don't have the official definition memorized but I would tend to reserve pwl for something that lasted more than a storm.

I agree with you, Ron.  Good description....  not sure PWL is what I would call it.
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Lowell_Skoog
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #90 on: 02/28/14, 01:30 PM »

I wonder if persistent weak layer is the right term for the slide we are talking about. In my mind it was all one big storm system and rather than looking at it differently from a trickier continental snowpack mindset I just viewed it all as a big dump that although settling enough to make trail breaking easier as time went on was far from bonded or bridged. I think labeling this as pwl is lending to much mystery to it rather than in terms of our normal multi foot storms where one expects natural releases and knows to use caution. I don't have the official definition memorized but I would tend to reserve pwl for something that lasted more than a storm.

The key, I think, is what happened BEFORE the big storm.

Think about the winter we've had. Months of below normal snow depth. Killer crusts formed in January, some new snow, then many days of sustained frigid weather (below zero F in many places). Then we got the big dump.

I'm just going from memory. Feel free to provide more detail.

That is not a typical Cascade weather scenario. If you'd like to bet your life that the layers underneath the 12+ feet of snow we received in February are just normal coastal snow layers, that's your privilege. If you bet wrong, I guess that's just "bad luck" (in Good2Go's words).

But it seems like a bad bet to me.

I'm going to assume there is a persistent weak layer out there and behave accordingly.
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BillK
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #91 on: 02/28/14, 01:53 PM »

Makes sense, you guys both make good points....I guess time will tell if it is "persistent" and continues to be "weak".  But I think your "assumption" and associated plan is a good one.   
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flowing alpy
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #92 on: 02/28/14, 01:56 PM »

Excellent TR.  Thank you for making the effort.  Glad it wasn't any worse than it was for everyone involved.

Couple of thoughts.

"Firstly, no one has a perfect handle on this stuff.

 Simply the amount of snow we have had recently and the extremely complicated terrain in the Alpental back country should make one extremely cautious. 

I think it is really hard to make your own snow safety decisions from the Internet and limited access to on sight field inspections.  Doing so in a huge storm cycle like we just saw is beyond most anyone, either from lack of experience or lack of education.   "Professional" or not.

There is an answer here.  Most just don't like it.  Including most of my partners.  Stay off complicated terrain until things settle down. (with all that implies)

Silly as it sounds, your life may depend on it.
they got lucky.
b
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RonL
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #93 on: 02/28/14, 02:27 PM »

Lowell, I am not going to take that bet, and I didn't that weekend. I am making the distintion because I think the label of pwl and all the attention that accompanies it gets applied too late for the incident at hand and likening it to continental regions is a bit vague to people not accustom to them. Whereas using the rule of thumb of being cautious after a big storm in the maritime climate can be applied before we get the kind of confirmation needed to call it a pwl. I would rather the summary of what went wrong focus on the aspects of this large amount of new snow will settle enough to give you some evidence of surface stability but it may not be the sort of stability strong enough to bridge the old storm layer regardless of whether that storm layer is just some old garden variety maritime crust or something that resembles the elevations and dyness of the Rockies. Time will tell if it was persistent but it was obviously deep and it failed. Perhaps someone will discover something truly unique about the snow down there but if they don't it may just point to ten feet of new has the potential to go big on many different types of crust that we often get in the nw and big steep open terrain should have a known warning on it.
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Lowell_Skoog
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #94 on: 02/28/14, 03:05 PM »

I am making the distintion because I think the label of pwl and all the attention that accompanies it gets applied too late for the incident at hand and likening it to continental regions is a bit vague to people not accustom to them. Whereas using the rule of thumb of being cautious after a big storm in the maritime climate can be applied before we get the kind of confirmation needed to call it a pwl. I would rather the summary of what went wrong focus on the aspects of this large amount of new snow will settle enough to give you some evidence of surface stability but it may not be the sort of stability strong enough to bridge the old storm layer regardless of whether that storm layer is just some old garden variety maritime crust or something that resembles the elevations and dyness of the Rockies. Time will tell if it was persistent but it was obviously deep and it failed. Perhaps someone will discover something truly unique about the snow down there but if they don't it may just point to ten feet of new has the potential to go big on many different types of crust that we often get in the nw and big steep open terrain should have a known warning on it.

Sounds fair, I guess.

If I understand you, you're reluctant to use the word "persistent" because it's too soon to do so.

I can go along with that. Instead, how about calling it a "Big Hairy Question Mark." It seems to me that's what it is. We can each decide how to deal with it.

I think it would be a mistake, however, to just forget about what happened before the big dump because it is now buried under several meters of snow. That's just willful amnesia. The snow doesn't forget. We shouldn't either.

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Lowell_Skoog
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #95 on: 02/28/14, 03:19 PM »

Perhaps someone will discover something truly unique about the snow down there but if they don't it may just point to ten feet of new has the potential to go big on many different types of crust that we often get in the nw and big steep open terrain should have a known warning on it.

After thinking about it a bit more, I see that your real point was that regardless of whether there was a funky layer down there, heading for the north side of Chair Peak (or the Slot Couloir for that matter) right after a big dump like that is a questionable call. I agree.
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aaron_wright
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #96 on: 02/28/14, 03:33 PM »

Sounds fair, I guess.

If I understand you, you're reluctant to use the word "persistent" because it's too soon to do so.

I can go along with that. Instead, how about calling it a "Big Hairy Question Mark." It seems to me that's what it is. We can each decide how to deal with it.

I think it would be a mistake, however, to just forget about what happened before the big dump because it is now buried under several meters of snow. That's just willful amnesia. The snow doesn't forget. We shouldn't either.


How about we call it a "giant f**king windslab" that would probably be most accurate.
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RonL
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #97 on: 02/28/14, 03:36 PM »

Actually, in the context of preplanning for a trip I do prefer big hairy question mark. I agree with incorporating the weather leading up to the storm too but I think if anything it makes the question mark hairier. I guess I am focusing more on why nwac and people in their trip reports and other sources people look to in preplanning might not be able to give a clear warning about this incident but other sources such as the prestorm weather, the amount of new snow, the lack of a big change in temps and no big bridging layer provide a big hairy question mark that should over ride the percieved green light a considerable rating, a couple surface stability tests, and other successful trip reports may have given one. I was just reacting to the thread drifting toward a pwl being the culprit and shifting the focus of off what could have been foreseen especially if after digging down ten feet and sweating like ski bum with his first mortgage one were to find no clear uniquely bad layer. That is way too much typing on a phone for now.
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flowing alpy
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #98 on: 02/28/14, 04:21 PM »

impressive
b
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hillybilly
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Re: Saturday February 22, 2014 Chair Peak Avalanche
« Reply #99 on: 02/28/14, 04:48 PM »

A cornice(or something large) was likely dislodged off Chair peak transferring enough energy and force to react the PWL on the face below.

This is consistent with that days forecast, the slide path and similar behavior was observed on the Alpental ridge in that same time period and on a related aspect. This is observable to any one who takes a moment to look out the high-gate.

It is unlikely that the skiers remotely triggered this specific slide since if that were the case we would have observed a much more active slide cycle during the storm and that simply hasn't been the case.

That PWL is there. It's in the slot as well which is an assumption I make but I think a likely one. Less sun exposed areas had the strongest crust and sandwiched faceted layers prior to the storm cycle. It will take some force to react that layer but it can be done in weird ways at weird times. That is the point of calling out a weak layer. They are hard to forecast and un-predictable.

I wouldn't be too terribly harsh on those skiers. In colorado if a PWL forecast meant not skiing BC then you wouldn't ski BC all year, every year. Know that this layer is out there. This is the risk you assume when you travel right now.

my 2c
« Last Edit: 02/28/14, 04:58 PM by crosson » Logged
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