Thoughts? Or just give it a read. The linked article is by Doug Chabot.
http://www.mtavalanche.com/sites/def...%20Digging.pdf
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Thoughts? Or just give it a read. The linked article is by Doug Chabot.
http://www.mtavalanche.com/sites/def...%20Digging.pdf
Objective (in)stability > subjective introspection. I like it.
I am not a professional but that has allways been my thoughts. About the ECT. My son told me he went to a presentation in Montana where it was said ECT results did not change with slope angle. Anyone want to elaborate?
If you could get everyone to just do an ECT and back off if it propagates that would be great. How many people will try and justify skiing the slope even with this evidence of instability?
It is a great simple idea and practice.
My understanding of this is that the ECT "measures" the propensity of a weak layer to support fracture propagation. The ability of a weak layer to support fx prop is independent of slope angle. It may be easier to initiate failure on a steeper slope but the propensity for fx prop in that layer remains the same regardless of the slope angle. Anybody feel free to call me out if I'm getting that wrong. I'm not very scientifical.Quote:
Originally Posted by BFD
Edit: Here's the link to the ISSW paper on ECTs and slope angle http://arc.lib.montana.edu/snow-scie...ISSW_O-010.pdf
From the article:What about terrain? Terrain, snowpack, weather, human factor. The 4-pointed avalanche triangle.Quote:
Identifying human-factors in conjunction with gathering relevant data is a winning combination.
The author is and always will be a vastly greater avalanche mind and professional than me. No disrespect intended in my above comments.
How about this as a discussion point - ignoring other factors and simplifying: perhaps it is worthwhile to qualify the value of ECT (and other) stability test results in the context of the current avalanche problem. If you have a reported PWL or DPWL in your area bulletin... perform an ECT and do not ski a slope if it propagates, or pops/drops. And only use stability tests below treeline and cautiously at treeline. The snowpack variability plus the consequences of being wrong in the alpine are too high to rely on any stability test results. Or perhaps negative results (no pop/drop/propagation) in the alpine should be ignored as too uncertain.
If you have a PWL or DPWL in your area bulletin then signs of instability (including recent avalanche activity) are absent or not obvious. And the article says this, which seems to agree with my thoughts:
I operate in a deep, warm snow regime with a quick velcro-like bonding habit. In my world, digging more often would not save lives. Respecting wind and storm related instability, group spacing in start zones and especially above terrain traps would. Human Factors + terrain use in my mountains play a bigger role than digging and testing. Articles like the one linked should be read in the context of the snow climate that they were written. But does the eager backcountry internet reader know that?Quote:
Digging is a reliable and quick way to search for instability when the signs are not obvious.
I really want to to repeat this: The author is and always will be a vastly greater avalanche mind and professional than me. No disrespect intended in my above comments. So please don't go looking for it.
Karl Birkeland promoted using the ECT at the Eastern Snow and Avalanche Workshop this past Fall because of the results being similar regardless of slope angle. Certainly got my attention.Quote:
Originally Posted by BFD
Edit: Karl was not saying it had the best correlation, but that the results of the ECT were consistent even as slope angle changed whereas the other pit tests did not show the same consistency.
Will read the article later tonight when I have a minute.
if youre discussing pits and no where in the article do the words "spatial variability" appear
well
dig more pits
cause your not gettin it
bush league at best
Fair point, especially if the snowpack is like cement deeper down, but in many cases I think they are worth it. See the linked CAIC Loveland video somebody posted. Spooky stuff and that is a shining example of 'well there is your answer'.Quote:
Originally Posted by neck beard
author has most certainly dug more pits than anyone on this forum.Quote:
Originally Posted by skifishbum
gnarhucker tried to dig ur moms pit
Can you ass wipes manage to keep the slide zone forum devoid of pissing matches and other bullshit?
You can always cross post to the PR but this place is generally free from that.
As someone who doesn't backcountry ski midwinter it's not usually something I do but it definitely brings a different viewpoint from someone who knows a hell of a lot more than me.
Recreational Avalanche training is trending away from digging pits, of any type, because despite Doug's excellent points about why we should dig more pits, it's human nature to come up with rationalizations not to. Emphasizing timing and safe terrain selection is intended to work with what people actually do. Most of the time I'm convinced I know what's going on in what is usually a stable snow-pack, and utilize much faster and simpler methods to test my hypothesis. That said, we're dealing with an unevenly distributed PWL (hoar frost on crust) at the moment, and as I'll be heading into new terrain later this morning, I'll be digging.
Snow pits have their place in forecasting.
For the casual to serious Back-country skier they can provide some window into what the snow is doing.
If you want to reduce your exposure to avalanche risk all that is required is to reduce slope angle and pay attention to aspect and your travel habits.
If you want to ski steeper slopes (which is much more exciting) pits won't really help you reduce risk all that much.
^^^ ftw
i really doubt ya could find many experts that would willfully disregard spatial variability in pit discussions
but he did manage a 2x pow magazine expert e-suckoff
Meh, Chabot is a good guy, a friend and knows his shit.
He has a good message:
I think the takeaway is, Don't rely on stability tests to make a GO decision. Listen to them to make a NO GO decision.Quote:
Most skiers have already made the decision to ski or not by the time they reached the top of their run,
but a critical question is still unanswered: what is under our feet? We can guess or we can know.
Knowledge is a powerful tool and personal responsibility requires due diligence. Introducing the human
factor into decision making will remain a large part of our avalanche education efforts, but we are now
pushing people to take one more step and perform an ECT before descending because sometimes the
snowpack surprises us with her answer. In our classes and videos we teach students how to execute this
test in under three minutes because we know it can save your life
Or in old school Wasatch speak there is always the , "Why bother with a pit when you are going to ski it anyway".
which is probably why the uac changed from know before you go forcasting of avvy probabilities and facts
to keeping you on top through trying to lower risk tolerances expert finger waving bloggity blah
Probably so.
I try to keep in mind my 1st Avi Courses were before TG/ET and back when Depth Hoar was the villain.
Times change.
It's nice when one pit lasts you the whole season.
A pit may not alter my decision to ski but it may vary the route of descent significantly.
This is the second time that you've mentioned spatial variability. Now you claim that Chabot willfully disregards spatial variability. I think the reason he doesn't mention spatial variability is that this is mostly an op-ed type piece encouraging folks to do a simple, quick test to evaluate instability because the ECT is quicker and less subjective than older snow pit evaluations. If anything, I would think this would encourage people to dig more and perform more ECTs and that addresses the spatial variability. This article didn't seem intended to be an in depth discussion of snow pits in general and the need to consider spatial variability when interpreting the results of your pit.Quote:
Originally Posted by skifishbum
Do you have some special insight into the author's mindset when he was writing this article? Do you have an axe to grind? The only thing I didn't care for was the mention of the "Human Factors" piece in Powder. It was anything but riveting, other than that is seemed like a thoughtful article with not a lot of "expert e-suckoff".
Agree with everything you said, but also would add that since that the piece comes from TAR (check the link address), and is therefore directed towards avalanche forecasters, educators, and other professionals, I'm guessing that he didn't feel the need to explain spatial variability to that demographic.Quote:
Originally Posted by AaronWright
Didn't catch that and it explains a lot. I don't know how much it will change my practice, I live in a weird area between coastal and intermountain snowpacks. Most of the time we're not dealing with PWLs and it's mostly storm snow instabilities but that seems to have changed the last few seasons with a shallower snowpack and wide temperature swings. Last week would have been good for the ECT, 2' of low density snow on a thin layer of surface hoar sitting on bulletproof crust. It was quite sensitive to propagation.Quote:
Originally Posted by adrenalated
Now with a very rapid warm up and some rain it is very strongly bridged but will likely be an issue when Spring rolls around.
A member of the "avalanche commission" of Hochfügen (resort in Austria) died a couple of days ago in a slide he was caught in while digging a pit - these are the people who decide whether a ski area or a run opens. They were next to a popular traverse which had been skied by dozens of people that day, along with the slope below the traverse. x marks where they were digging, arrow where person was buried, red line is traverse track. This has nothing to do with the article and I have no point I'm trying to make, just came to mind... bit of a "where are our gods now" feeling.
http://1.bp.blogspot.com/-PXpQgSB5qE...002-785132.jpg
Wow, looks like if he was a few feet to skiers' left he'd be alive. That snow fence would have stopped him.
The biggest thing wrong with pit digging I have seen in my three years of skiing is people digging pits in really unsafe locations and situations. The post by Klar reminded me of a few days yelling at uber noobs to get the hell out of where they were, the whoophing noise present at the pit digging time. (us descending after digging two pits - one at the base; good to go results and one mid way up; no go results)
Pit digging and gut feelings combined make our decisions in the back country. I wish avy courses would focus on location of pit digging and how to do it safely. I was lucky enough to do a work shop with Doug and Mike.
I think the important thing to take away from this is to take other people's results with a grain of salt. If you worry about a pit not being next to the line skied, how much weight can you give them anyway?Quote:
Originally Posted by ecowhit
On the upside, the whole test is designed to sacrifice precision in favor of tools you have and time you're willing to spend; I certainly hope anyone taking data and writing forecasts sees it accordingly.
Damn, I give plenty of thought on where (and when) I dig a pit. I'll be thinking more about it now....