Thread: emphasis on pits and snow science in decisionmaking

from the romeo/onufer thread, leelau wrote:

Originally Posted by LeeLau

jserra - I think most people would disagree with your emphasis on pits and snow science. If you want a discussion about that; start another thread and I think you'll get useful discussion.

which was in response to jserra's post (which I snipped):

Originally Posted by jserra17

It seems that this (Slide Zone) forum has become highly dysfunctional. As of this week, we have 30 dead in avalanches in the U.S. At this point, an honest discussion about avalanche risk and intelligent decision making is appropriate, if not absolutely necessary. Yet, in every thread, any suggestion that applying a disciplined decision making process might have avoided a tragic outcome is met with howls of protest. Those processes are taught by AIARE, AAI and their Canadian equivalent - all of the professional avalanche education organizations in North America. I find it ironic that in this case my suggestion that the victims had followed those protocols has lead to still more protest. It's as though suggesting that someone followed safe procedure is an accusation that they abandoned some unwritten code of hard-core backcountry skiers. If that colony of backcountry skiers and riders is so sure they are right about their approach, why the extreme sensitivity? If those people really think they are safer by not digging a pit and performing some basic analysis, why the vitriolic response?

Forums are supposed to be about opinions. While there is no need to be hurtful or disrespectful, an honest discussion about these incidents is what one should expect in a forum and attempts to shout down those who offer opinions on that subject says more about the insecurity of the protestors than the competency of those offering the opinions.

Ok, so here's my opinion and bias: As a former professional Heli-ski guide with both AIARE and AAI Level 2 certifications, I believe that you shouldn't be out there if you aren't willing to take ten minutes to dig a pit to see what's actually happening in the snow pack. You should have done some research before leaving home, but still have an open mind about what you will find, what you will ski/ride and whether to turn around and accept that it was just a good day for a hike. If you are an occasional backcountry skier/rider, you should take a Level 1 class. If your life is built around "crushing it" in the backcountry, you should take a Level 2 course. In both cases, you have to apply what you are taught - a certification without that is just a piece of paper. Taking those steps won't guarantee your safety - you can do everything right and still be at risk. Not taking steps to mitigate the risks is foolish.

You are welcome to disagree. That's what forums are for.

Peace.

i'm starting this thread because i'd like to observe (and maybe participate) in a useful discussion on this discourse. hopefully, some of the extremely experienced folks and professionals will give input.

(i'm happy to delete this thread is this proactive approach is stupid)

cheers

I believe most BC travelers can make use of snowpits on many or most of their days out if they understand how to use the information, its limitations, and appropriate application. Relevant thread: SNOW PITS... good or good for nothing?:
http://www.tetongravity.com/forums/s...od-for-nothing

We cannot control for all error and variability. Therefor prudence demands erring towards the conservative the greater uncertainty. But, we have to accept some risk to play the game. How much?

Most avalanche education organizations do not utilize concrete formulaic decision trees. Those algorithms do exist. Excerpt from another thread:

Originally Posted by Summit

IS THE RISK ACCEPTABLE?

Only you can decide what risk is acceptable. However, humans are awful at estimating risks and making risk part of the decision making process. I'm not going to tell you how to make decisions in this thread, but I am going to arm you with some tools to think about risk assessment that can help a great deal. Then you can more accurately decide if a risk is acceptable.

When your local avalanche center tells you the avalanche danger is forecasted at CONSIDERABLE, what do they mean and how do you use that to figure out risk? One can make a discussion of risk very complex with algorithms and rule based systems. There are mathematical risk reduction systems like Nivotest, Munter 3x3, and Avulatorthat come on plastic cards you can consult in the backcountry. There are even applications like AvaRisk for your smart phone to do the math for you.

Read the rest here: http://www.tetongravity.com/forums/s...sk-(with-pics)

I think I understand jserra's point of irritation, that there are a lot people who make decisions based more on feeling than fact. It is a major trap to believe one can make decisions with certainty using uncertain information. To do so is very human. Most people get away with it most of the time. Humans suck at making decisions about low frequency, high consequence, high reward situations. We can (and should) encourage more rational decision making, but the actionable information will always be limited. I think that some people look at that inevitable uncertainty and say, "why bother," either out of frustration or laziness.

What I won't accept is the idea that such action can merely be chalked up to "higher risk acceptance" in most cases. Risk acceptance is an overused term in this context. It is an inappropriate concept bring up with users of the winter backcountry until they have at least a Level I knowledge equivelent and a decent amount of experience. I think it is more of a Level II topic.

Thanks Summit - I knew there was good discussion about that somewhere!

Maybe they base decisions on feeling not fact because contemporary any education sucks?

I cannot find the study with a brief bit of googling, but there was one I read that basically said that your typical backcountry skier doesn't have enough skills / training to properly assess snowpack based on the results of snow stability tests.

some of us just don't care about snow pit data all that much. i know i don't. never have. i'm purely there to ski and i use my own methods like, following precip, winds, the previous tours observations, and lots of pole probing verses standing around digging and studying what's below the surface.

rog

natew08
I agree that the limits of the artisan limit the application of the craft. That doesn't mean that there is no use for pits. I discuss that here: http://www.tetongravity.com/forums/s...od-for-nothing

Originally Posted by Summit

The Breadth of Field Snow Science Observation and Application

Pits are wonderful. I'm a geek. I love them. That said, more hasty pits and hand pits are better than one data pit etc etc because you increase your sample size to combat spatial variability on both the small and large scale. How information from pits becomes useful is dependent on the skill level, experience, education, and goals of the practitioner:

I've written on this subject in Slide Zone with regard to what the recreationist with a Level 1 should be doing with pits, reasons to say no: looking to see if the pack is worse than forecasted or if some unknown danger exists plus improving their understanding of the processes at work in the snowpack.

People who are out very often who have more experience and better understanding can do the above with perhaps a little better discrimination by using more pits to form generalizations of the snowpack as it varies between elevations, aspects, angles, mountains, ranges, etc. This sort of information can allow so called "now-casting."

More experience, education, and frequent observation by the professional combined with interprofessional communication and review can allow advanced practitioners to forecast.

Obviously, my little summary here is quite anemic and leaves out many factors involved...

icelanticskier:

Doing what you do is excellent and can provide much of the information a pit can provide (and information a pit won't provide). Ideally, everyone should do the things that you listed, especially as it helps to pick reasonable options when touring. Your experience makes your methods efficient, but not everyone has the advanced knowledge and experience to apply the information. Additionally, I don't think your methodology is very sensitive to micro-climactic variation. Certainly, pole probing is not sensitive to many stability problems that either evolved or occurred inbetween your presence in a frequented area, much less an area you do not frequent often. I'm not saying your way is wrong, just that pits could be useful to you too.

Originally Posted by natew08

I cannot find the study with a brief bit of googling, but there was one I read that basically said that your typical backcountry skier doesn't have enough skills / training to properly assess snowpack based on the results of snow stability tests.

We hear this a lot from the forecasters at UAC and CAIC - they don't trust stability test and pit profile data submitted by your basic civilian. One guy can provide more force in 15 shovel taps than another does in 50.

The Icelantic method can work well if you are in an area a lot and there's not a lot of change in temp, snowfall, etc. Me, I'm a snow geek and like to dig around at look at crystals with microscopes. That said, like Summit I tend to go with many hand-pits instead of one large pit - unless deep slab issues might be present.

To Hugh's point above, I think there's a focus on snow science in Avy courses because those principles can be objectively taught. You can't really teach people how to read terrain or recognize/overcome the Human Factors in two field day exercises - that's gotta come through experience.

This thread is a good topic and already has some great contributions. thanks for starting it.

here are a few of my disorganized thoughts on the issues:

Snowpits have value to both professionals and the average backcountry user. personally, i don't use them very often but i get a lot out it when i do dig. first, you have to know why you're digging (baseline for a new area, tracking a particular layer, crown profile, etc). to make the decision to ski a slope based on a pit is not one of those reasons for me to dig. by that i mean i would not ski a slope solely based on finding good signs of stability in my pit, especially if other data gathered along the way pointed to possible instability. when dug on a slope you intend to ski, a pit can be a final confirmation of the "big picture" that you gathered from avy/weather forecasts, previous weather, witnessed conditions/activity, etc. When a pit disagrees with the "big picture", more assessment is needed but err on the side of caution when things are less clear.

Time is also a big drawback of a snowpit. if you were to dig on every aspect and elevation that you crossed or skied you wouldn't make it very far. choosing when a where to dig are arts in themselves. again, you should be able to answer why you are digging there before you begin.

fwiw, I'm also leery of using pit data gathered by sources i don't personally know. too often people will use pit tests that are inappropriate for the type of instability in question. they may also get poor feedback in a pit based on sloppy pit work and failure to isolate columns properly.

Gut feelings are developed over time but not always understood. for me, i don't use a gut feeling to ski slopes that are otherwise questionable. my gut does have the ultimate veto power when it's saying something is wrong here. no pit will over ride my gut feeling when it's telling my no go.

when instabilities are present, don't try to overthink the snow. humans can rationalize almost anything if they think about it long enough.

Originally Posted by AltaPowderDaze

when instabilities are present, don't try to overthink the snow. humans can rationalize almost anything if they think about it long enough

When I first started touring, I would traverse dangerous slopes by going very slowly, smoothly and quietly. For some mystic reason, I thought my meditative pensiveness and constant watching of the hill could change the likelihood of a slide.

I am here today. So it must work

It would have been more instructive to dig the occasional test pit. However, that would mean digging pits on the same slopes that might slide ... and then I might trigger a slide just by digging the pit. That is also some probably retarded reasoning.

So, now I employ plan B -- change route to avoid avalanche terrain!

I am here today. So it must also work

for being cool guys^^^^^^^.

i know i can be abrasive. spending a lot of time in one mtn range is a big reason for no digging for me. in my wasatch winters i never once dug a pit either. even when i did field days with my touring partner, one of the head forecasters for UAC up to 6 days a week all winter, we never dug pits either. our focus was proper terrain travel/management and tons of pole handle probing as mentioned in my post.

great discussion.

rog

I've been watching a lot of Bruce's videos lately. Good stuff.

Here's a really good one on interpreting pit results

The goal of backcountry avalanche forecasting is to minimize uncertainty about instability by prioritizing information acquired through a model of the physical processes taking place in the mountain environment while accounting for the possibility of human error.

* Decisions require information about what's been going on in the mountains along with a margin of error for when we're wrong.
* Our mental model of the physical processes is formed by observing the terrain, weather, and snowpack.
* Snowpack is the product of the chaotic interaction between terrain and weather.

Ask yourself the following question:

* How -precise- is your model of the physical processes taking place in the mountain environment?
* Precision means how many factors and connections between factors are included.
* Terrain, weather, and snowpack is a low precision model.

Ask yourself the following question:

* How -accurate- is your model of the physical processes taking place in the mountain environment?
* Accuracy means the rate of error in the data you've collected.
* There are likely to be inaccuracies in most models of the physical processes taking place in the mountains.

I think the debate is less about whether or not to use snowpack observations, and more about whether or not an individual is actually qualified to use snowpack observations. For unqualified individuals, any type of observation can do more harm than good. ( The Avalanche Handbook discusses how data sampling may have positive or negative influence on our perception. )

* Recreational observations of terrain, weather, and snowpack are often very basic.
* This implies a low precision model of the processes taking place in the mountains.
* Recreational observations are more likely to contain inaccuracies.

Therefore:

* Recreational decisions use low resolution models that contain frequent inaccuracies.
* But obviously, the snowpack is usually stable, so we usually get away with it! ( Thanks HomeMadeSalsa! )
* Many decisions have more in common with gambling than risk management.

I think people should use as many observations as possible, including snowpack obs, but the elephant in the room is that most recreational skiers lack the knowledge to develop a high-precision, high-accuracy model of what's going on in the mountains.

I have been thinking about this issue for the entire winter as I teach avalanche classes. I do think we have a lot better tools and systems now than we ever did. The real problem, I believe, is of course the human factor, the backcountry psychology as Cookie Monster calls it. We have a certain willful naivete that allows us to do what we WANT to do, rather than what the clues point us towards, and the forgiving nature of the snowpack allows us to get away with it.

I do want to hit on some of the new approaches and tools, as they speak to the original question: use of snowpits over-rated?

Much of the new approach involves trying to figure out what our primary/ secondary snowpack problems are. Many of your forecasts give you this information (eg Wasatch, Sawtooth) but it is always in meta-information, so you need to go confirm or deny the info. I love the quote from Ed LaChapelle that someone brought to the table in the previous thread (Summit was that you?) because it truly is about hypothesis testing without being attached to the results.

With direct action problems (storm snow, point release, wind slab), focused sampling can give a very good understanding of the extent and sensitivity of the problem. Ski cuts work, pole probing is an excellent tool, my favorite tool is the hand shear or hand pit, esp if the problem is within half a meter of the surface. Detactability and manageability are generally both high, especially if you have a representative weather station to see the hx, so you are not sideswiped by wind slab formed by high winds creating wind slab further down the slope, for instance.

With an indirect problem, aka a persistent weak layer (PWL), these tools are still useful, but don't give as full a picture. If I am tracking buried surface hoar half a meter down, then detectability goes waaay down, as does manageability. I want/ need more information, especially as the time of formation of the original layer is extended. Then I want to know what kind of energy is still residual in the interface between the slab and the weak layer, and I want to know the structural issues in that interface as well. I rarely do a full data pit unless in an institutional setting or a new snowpack. I will very often do an ECT to investigate the propagation propensity of that buried PWL, or look at the lemons in the relevant interface structure to see changes over time. With a deep slab problem I may do a PST to see if the energy has been dissipated. Think about how surface hoar loses its toxicity: through layer thinning. Rather than speculating about whether it has enough load to penetrate above and below, I am going to dig down and have a look, whack on it and see, then do a ski cut in a safe spot to further hypothesis test.

All this information is then collated with everything I have been seeing, everyone else seeing, to help me create a rose of the problem. I never just dig a snowpit because I think I am supposed to... I dig one because I have a set of questions that need answers, and I have the experience (because I have dug and taught them for years) to get the information quickly, efficiently, and accurately. Gotta become accurate first (this takes time and mentorship), then you get tips and tricks for efficiency, then finally you are quick at it.

So there is a little of what I both practice and teach.

I do think that many many people have been making excellent calls during this difficult winter, reining it in, reading the terrain, using critical thinking to make good decisions. As has been said before, most of this season's accidents are in one of two camps: first the ignorant who don't know any better- say no more. But the second camp is the so-called experts, and most of these accidents come from underestimating the problem, especially a PWL or deep slab problem. This I know from experience is really a human factor problem, exacerbated by a plush season the year before, where we could go anywhere, do anything with impunity.

I have been thinking a lot about Bruce's graph from Staying Alive about how we are brave and bold, then something happens to bring us back to humility, and then the cycle continues. Over time we try to hone our skills, make tighter decisions closer to the edge, but since snow and avalanches are still an inexact science we find the edge often by going beyond it. Only by honest self-examination and sometimes clarity from others outside our circles can we gain perspective enough to truly learn.

FWIW, on a very general and rough level the Europeans don't seem to dig any snowpits at all while the North-Americans seem to be all fascinated about them..

I have done two avy courses in Europe, 2 and 4 days respectively, maybe something like what would be avy1 and avy2 equivalent in USA, and during the whole time we did one rutschblock test and that was it. This was 3-4 years ago.. The courses tend to concentrate on route planning, human factor, and generally making informed decisions about the terrain based on the avalanche bulletin and weather etc.

Personally I also never really do any snowpits and consider them to be quite useless for my decision making. I might dig one or two when I am in a new area just so get a rough idea about the snowpack. I have skied in Canada and seen a "nearly fresh from avy1" persons digging snowpits while we were touring and making some dangerous and uninformed decisions based on just one or two snowpits and ignoring other obvious data.

None of the people I go touring/skiing with dig any snowpits either. So clearly the two continents are in two different camps again.

test slope. they're everywhere.

Originally Posted by keksie

FWIW, on a very general and rough level the Europeans don't seem to dig any snowpits at all while the North-Americans seem to be all fascinated about them..

I have done two avy courses in Europe, 2 and 4 days respectively, maybe something like what would be avy1 and avy2 equivalent in USA, and during the whole time we did one rutschblock test and that was it. This was 3-4 years ago.. The courses tend to concentrate on route planning, human factor, and generally making informed decisions about the terrain based on the avalanche bulletin and weather etc.

Things are changing. You just described the Canadian AST Level 1 (2 day intro course).

My asshole, I mean, opinion:

Pit stability tests as a data input to slope assessment: limited value to me personally, though I do use them to confirm that a start zone is indeed loaded with an unstable slab and that it probably wouldn't take much force to rip it out.

Snow profiles as a part of the slow process of developing an understanding for snow, how the snowpack relates to weather, how laying changes over time, how it relates to the professional bulletins and recent avalanche activity.... that is all part of the journey from rigid rule-based slope assessments to knowledge and intuition based slope assessments. I encourage people to start on that journey early, so therefore encourage them to dig into their snow and know it (but to not bother falling in love with the apparent "intelligence" bestowed by pit stability tests beyond learning about stress v.s. strength in a layer of interest that should not be correlated to a skier on the slope).

We have a persistent weak layer at the moment and I dig for it every day to see how it changes with respect to time, weather and generally the depth of snow between it and the atmosphere. It is interesting and educational - and helping me build just a little more personal intuition, which takes so many season's and different snowpacks to build over time. No opportunity should be wasted, no matter how knowledgable you think you are.

I'm a huge advocate of digging pits.
I make most of my decisions by observing weather patterns and following observations from other backcountry skiers and avy centers. Before going towards a committing line, I have a good idea in my head about whats going on under the snow... what layers or interfaces I'm worried about, how deep they are, how long they've been gaining strength, what the general stability is for that aspect, etc. and plan my exposure accordingly. But then I dig pits or hand pits alot to verify what I suspect is going on and observe how it changes across slopes. Maybe a spatially isolated layer formed that you couldn't have predicted from watching the weather or reading observations. Maybe that layer that you thought should be well bonded by now isn't on this particular slope. Maybe that benign 6" that fell overnight got very loaded on this feature so you need to be more heads up. So the pits are often targeting instabilities; trying to prove myself wrong on a slope that I've already pre-assessed as being stable. They aren't used to prove a slope that has all sorts of red flags is suddenly good to go.
They aren't time consuming if you have a targeted question and your backcountry partners are capable of helping. It takes about 5-10 minutes to identify layers and lemons, and crank out a quick ECT and CT while you catch your breath and snack on some food. For getting acquainted with a new snowpack with an unknown snowpack history, its obviously not so hasty but even more important.

I agree that a newbie in the backcountry might not be able to make informed decisions from a snowpit, thus targeting bigger picture ideas like recent loading, avalanche activity, whumphing/cracking, rapid warming, etc are more important. But the more you dig down and correlate what you're seeing with others' observations and natural avalanche activity, the better grasp you'll have with slope stability analysis in the long run. The ECT has some pretty easy interpretations that could prevent accidents if people took 5 minutes to do one.

5-10 minutes a pit (and this is on the short side all in I think, particularly in a maritime snowpack) is most definitely time consuming if you are digging multiple pits.

< shrug > still lots of hand waving about "understanding" "decision making" blah blah blah without being able to either explain these thought processes or demonstrate them aside from ipso facto they're alive.

Originally Posted by keksie

FWIW, on a very general and rough level the Europeans don't seem to dig any snowpits at all while the North-Americans seem to be all fascinated about them..

I have done two avy courses in Europe, 2 and 4 days respectively, maybe something like what would be avy1 and avy2 equivalent in USA, and during the whole time we did one rutschblock test and that was it. This was 3-4 years ago.. The courses tend to concentrate on route planning, human factor, and generally making informed decisions about the terrain based on the avalanche bulletin and weather etc.

Personally I also never really do any snowpits and consider them to be quite useless for my decision making. I might dig one or two when I am in a new area just so get a rough idea about the snowpack. I have skied in Canada and seen a "nearly fresh from avy1" persons digging snowpits while we were touring and making some dangerous and uninformed decisions based on just one or two snowpits and ignoring other obvious data.

None of the people I go touring/skiing with dig any snowpits either. So clearly the two continents are in two different camps again.

In Europe there is a huge amount more data available about the snowpack than is typically the case in North America. There are many more weather stations, as well as professionals doing avalanche control work in almost every valley and aspect due to the presence of roads, buildings, lift stations and huts densely seeded throughout the mountains. Further, due to the high density of backcountry skiers including many trained professionals (in particular guides) in much of Europe the information about recent instability and avalanche activity is typically much better than almost anywhere in North America.

A Chamonix guide I know once told me that he never dug pits in the alps, but when he went to northern Norway or Kamchatka, he did.

While pit data can give you a lot of usefull info in general about a particular slope or area, it can only be applied to that one particular aspect. Variations in terrain, wind and other factors change drastically not too far from where you dug the pit. I think one can garner most of the relevant info a pit would give by reading the most current avalanche bulletin from a forecaster in that region who's job it is to go around digging pits and assessing terrain.

I started skiing backcountry in the Wasatch back in 1992 and the 1st avalanche course I took through the U of U with Kirk Nichols emphasized meadow skipping and avoiding avalanche prone terrain all together. Kick off the skis and swim! Obviously, gear technology has changed the game considerably and some of those techniques are outdated, but I think a lot those sentiments still ring true; especially for folks just getting into the game. The most important skills one can have accessing backcountry terrain are common sense and sticking to the basics more than understanding snow science or pit data. Lots of backcountry enthusiasts like to geek out on the stuff, but common sense will keep you alive.

Read the most current avalanche bulletin and stay home if it seems over your head! Don't load up a slope, stay away from concave terrain traps, convex rollovers and unsupported slopes; etc... Always have an island of safety that is easy to get at. Try to ski on the apex of the terrain, so if something goes, it all happens below you. Obvious stuff to anyone who's spent time in the backcountry. I think the difference between life and death is having the discipline to stick to the basics and never get complacent.

Personally, I spend most of my backcountry time skiing the same terrain that I know fairly well. Yeah, that's boring and I'm not pushing my boundaries, but a steep couloir is a steep couloir is a steep couloir no matter where you are. It also means I have intimate knowledge of the terrain on a regular basis, know where the triggers are going to happen and knowing when to stay off it if conditions are too dicey. I never dig pits and don't really get off on the science of it all, so I just stick to the basics and that's done well by me for 20yrs (knocking on wood)!

My two cents... I'm very new to the backcountry so maybe I'm completely off base here, but here's why I like to dig pits every so often. A lot of the stuff folks talk about on this forum in and around terrain choices, avalanche decision making And the consequences of poor decisions I've only read about. So what like to do is use snow pits on test slopes so that I can see how terrain variation can affect snow stability for my own eyes. Will I use it to justify skiing a sketchy slope? No. But I find that it helps reinforce lessons from either books or people who are more experienced than I.