I saw a boarder release an avalanche after an unnecessary tight turn with deep edge cut into the pack
Sounds like the classic scenario where the second guy down follows in the tracks of the first guy, thereby cutting down to the weak layer... Not something you (as the first guy) can control. Best not to be there in the first place
Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
@SnoodyMcFlude, again, I'm not saying skiing fast/smooth is a suitable avoidance strategy. I always say if your in an avalanche you already made some big mistakes. My point was actually more the opposite, are weaker skiers venturing off piste putting themselves in more risk? Watching that video of the guy fall and get caught in the slide - if he doesn't fall and rides a bit faster imo he makes the traverse. I do think fast/smooth skiers probably "get away" with somethings. Less pressure on snow, no falls, less wide "traversy" turns, less time in general in avalanche terrain. These things are only going to reduce your odds of triggering something compared to the less skilled rider on the same slope.
@Steilhang, I'm not sure it's really that "classic". The majority of time the first guy triggers the slide. If the week layer is really so close to the surface the first guy was probably more lucky than a good decision.
As much as people spout "tracks don't mean it's safe" there is really no better test of a slope than someone skiing it before you. As Bruce Tremper says "never go first". Of course people will point to someone triggering a slide where there's tracks, but often the tracks are >30degrees and the person goes further left or right into >30 degree terrain, so not really apples to apples you are basically skiing a different slope.
Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
I was at a conference this week and one of the presenters gave a fascinating talk about his academic research into why people who know and understand the risks still take them - and how they did the research. He’s written a book on it. But in broad terms young guys in a group way more likely to take a punt on safety.
Then you can post your own questions or snow reports...
Then you can post your own questions or snow reports...
BobinCH wrote:
SnoodyMcFlude wrote:
@boarder2020, I thought he explained quite clearly how experienced professionals can make those mistakes. That's not excusing it of course.
My understanding is that they were not skiing the slope but were traversing out on the valley floor and were hit by the avalanche in the run off area. Did they remote trigger it or was it just terrible timing? Seems it’s very rare for that particular slope to avalanche (the guide says old growth forest avis are very rare) but the combo of a very bad weak layer and huge amounts of fresh snow created an anomaly.
Seems they did have an alternative route out but it was much longer and there’s a suspicion (in the comments) that commercial pressure came into play
The Aspect Avi guy did a followup after more details emerged. While he avoids explicitly blaming anyone and acknowledges the real commercial pressure, the guides decisions appear highly questionable, particularly in the context of a freakish storm and the known avalanche report warning of a persistent weak layer on north facing slopes
The "companion rescue" bit seems text book.
Remarkable also how compact the burial zone was.
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phil_w wrote:
The "companion rescue" bit seems text book.
Remarkable also how compact the burial zone was.
Me too. I wonder if that suggests that they weren't carried far by the avalanche and we're basically all stood in one location? Possibly stopping to wait for the other two to catch up?
The other thing that surprises me is the presence of reasonable sized trees which looks like they'd have provided at least some shielding from the slide.
And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
Even if they were all stood in that location there is no way 13 skiers with skis on, in deep snow or otherwise would squash in that tight. Even in a whiteout it doesn't make sense you'd be constantly bumping into the person in front and coming in on top of their skis. Either the infographic is wrong or they were somehow all compacted from a wider spread into that one area? 13 skiers in 20 feet?
Am inclined to agree that judgments based on just 2 accounts of the survivors are of limited value. Slide site also looks pretty inoccuous from below. Between that and the trees I think 99% of us would have been happy to traverse across, and in a whiteout they wouldn't even have seen the slope above.
So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much
So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much
It does seem remarkably compact.
Perhaps they'd stopped - not in an island of safety, clearly. They were right at the end of the slide path, on the trail (see map in report). It hit, they were in the terrain trap...
Having seen trees flattened only by air blast from slides, I'm surprised the trees were unaffected.
You know it makes sense.
You know it makes sense.
If they were (found) on the trail it makes even less sense. They couldn't have been that compact unless they were swept into that compaction by a terrain trap. But it doesn't look like there was a terrain trap there? Again, I think the info in the public domain now isn't good quality. I wonder could it just be a misreporting in that photo or in the account that led to that photo.
Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
Terrifying photo from Kuhtai in Austria.
1 German snowboarder dead after well tracked slope slid on persistent weak layer
The "companion rescue" bit seems text book.
Remarkable also how compact the burial zone was.
Me too. I wonder if that suggests that they weren't carried far by the avalanche and we're basically all stood in one location? Possibly stopping to wait for the other two to catch up?
Not according to the surviving member who was part of the main group. They weren’t stopped.
Quote:
The other thing that surprises me is the presence of reasonable sized trees which looks like they'd have provided at least some shielding from the slide
Yes, it’s remarkable.
8611 wrote:
If they were (found) on the trail it makes even less sense. They couldn't have been that compact unless they were swept into that compaction by a terrain trap. But it doesn't look like there was a terrain trap there? Again, I think the info in the public domain now isn't good quality. I wonder could it just be a misreporting in that photo or in the account that led to that photo.
Some of the “public domain” information are official reports. And it seems to me quite clear:
“The party was buried in a small depression in the terrain, bounded by trees and boulders, which likely allowed debris to pile up in that small area. ”, according to the Sierra Avalanche Center’s report.
“Small depression in the terrain bounded by trees and boulders” sounds remarkably like a terrain trap?
I’m not sure how much “better quality” can it be given only 2 survivors had spoken, and neither of them were guide.
Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
Nearly 4pm seems incredibly late to be skiing. But I don't know local temperatures or aspect of that slope.
Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
Yeah I appreciate they are official documents I still can't understand how the victims would have been so compacted. I'm only going on the photo re terrain trap. It doesn't look like (much) of one, or at least not one that could compact the group into 20 feet? The slide was 100 feet wide.
The same way a wide river becomes a narrow one. The shape of the terrain funnels the snow and the debris fills the hollow, stopping there..
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Anyway, snowHeads is much more fun if you do.
Perhaps the standing trees are an indication? It’s the toe of the avalanche. The force is less so the flow is redirected by the trees into the tiny “depression” forming a terrain trap?
That is an excellent piece @phil_w, thanks for posting.
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snowHeads are a friendly bunch.
Quote:
This season’s avalanche accidents show how difficult such weak layers are to manage and predict
Disagree. The snowpack was obviously dangerous. A lot of the deaths were on days where avalanche forecast was high, with snow failing exactly as predicted.
We have to get away from this concept of avalanches being unpredictable and skiers triggering them "unlucky".
And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
Another guide lost his life in the Ecrins yesterday
I was ski-touring on the Combeynot face the day before, not too far away as the crow flies, though at a lower altitude, and we played it safe, opting for a ski and not going into possible questionable terrain as there was so much loose coming down after two days of snow falling above 2,200 which was wet given the time of year, though it was only risk 2 in Thabor and 3 in Pelvoux.
So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much
So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much
boarder2020 wrote:
Quote:
This season’s avalanche accidents show how difficult such weak layers are to manage and predict
Disagree. The snowpack was obviously dangerous.
Disagree....
The snow pack being obviously "dangerous" is because the long-term effect of PWL are hard to predict.
Sure - many people died this winter on cat-4 days in places where they should not have been.
However: look at the picture from Austria above.
Well tracked spring slope that slid on layer created several months previous.
Once a weak layer is well buried then it takes much more than simple freeze thaw cycle to remove it from the snow pack.
Avalanches can be triggered months later. Simply by additional load of new snow or warmer spring weather.
You know it makes sense.
You know it makes sense.
boarder2020 wrote:
We have to get away from this concept of avalanches being unpredictable
Actually, the concept we need to get away from is avalanches being predictable!
”Moderate” or even low risk isn’t the same as no risk (like in resorts, on piste). Some people are taking the “prediction” too literally and accept higher and higher risk. With more and more people going touring, it’s only too “predictable” more individuals will get caught by statistics.
Stay away from all the borderline terrain and days. You’ll miss a lot of good powder days. But you may live to ski a lot more years.
Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
I actually think these two things - "This season’s avalanche accidents show how difficult such weak layers are to manage and predict" and "The snowpack was obviously dangerous." - can both be true at the same time.
The first sentence acknowledges that there are weak layers and therefore recognises there is danger (or heightened danger). This leads to: we can predict there will be more avalanches. But then there is the question of how predictable they are and/or how we manage this danger.
Statistically in the UK road accidents are 25% higher in November (he highest) compared to April (the lowest). Why is that and why can't it be eliminated. And the thing with the snowpack is it will change year to year....
Poster: A snowHead
Poster: A snowHead
Aye.
You can to some extent predict some avalanche risks. See "The Darkest White" for a beautiful book length example. Or ride somewhere where you can see the slide activity. Or dig a pit or two and check the profile. Or ask what the resort is predicting. Of course you can predict risks, the question is more something like: how accurate can those predictions ever be? The referenced article precisely makes exactly that point.
Sometimes people are overconfident in their prediction skills. They over estimate the accuracy of their prediction that it won't slide. Most times those are probably tourists, but not always. The Canadian avalanche training stuff all makes a big deal about not falling into that "I'm an expert" trap. It's a well known problem.
That happens a lot on the internet. I'm not sure if it's point scoring, or something else, but the nuance of is lost, somehow.
And "we need to..", often seems to actually mean: "I think you should..."
Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
Quote:
Avalanches can be triggered months later. Simply by additional load of new snow or warmer spring weather.
Exactly, we know that these things increase risk. Again very predictable that on the first warm day risk will be higher. Very predictable that after a big storm risk will be higher.
Go through the avalanche death reports and look at what percentage were people that made good decisions on low risk day and just happened to be "unlucky". The vast majority are people doing completely dumb stuff that you don't need hindsight to know was risky. Look at the avalanches people die in with the forecasts for that day, and you will see overwhelmingly the forecast not only predicted the risk, but the specific factors causing the slide e.g. wind slabs on north slopes.
There are literally whole books (and very good ones!) about how to predict avalanches and minimise risk. Go read all 300+ pages of Trempler's book and tell me avalanches are some unpredictable thing we don't have much control over
Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
boarder2020 wrote:
Go read all 300+ pages of Trempler's book and tell me avalanches are some unpredictable thing we don't have much control over
Is he/you trying to argue that avalanches (in detail not in general) are entirely predictable and/or we have control over?
Go read all 300+ pages of Trempler's book and tell me avalanches are some unpredictable thing we don't have much control over
Is he/you trying to argue that avalanches (in detail not in general) are entirely predictable and/or we have control over?
I feel way less safe of crowded pistes where out on control skiers and people behaving in unpredictable ways can hit me! Off piste offers far more control, especially when most of the time I'm simply avoiding avalanche terrain.
Avalanches are very predictable. Dig a pit, study the forecast and the known problems, know about terrain traps, etc. and you will massively reduce your risk. Not to 0, but you can get pretty close. For those that are going to say "it's not zero so it's not predictable", what percentage risk are you happy to take? Planes crash, but you'd be stupid to say plane travel is not predictably safe.
All the avalanche deaths are recorded with pretty detailed reports. Go read them yourself. You will nearly always see huge mistakes made by the group. You will nearly always see the avalanche happened on exactly the weak layer caused by the exact problems forecasted that day. I keep asking people to show me the report where a group made good decisions and just got "unlucky" but no one ever does. I mean I'm sure there must be a case, but they are still the exception to the rule.
Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
Often the issue is very low risk but high consequence problems. That’s getting close to unlucky
I keep asking people to show me the report where a group made good decisions and just got "unlucky" but no one ever does. I mean I'm sure there must be a case, but they are still the exception to the rule.
But there is a the potential counter side to that. How many instances has someone done the work, 'predicted' that an avalanche is likely and then someone else skis it and there has been no slide?
For all the examples that you don't your hindsight glasses, there will be thousands of other examples where someone has made a bad decision and skied away from it.
Then you can post your own questions or snow reports...
Then you can post your own questions or snow reports...
boarder2020 wrote:
... Avalanches are very predictable. Dig a pit, study the forecast and the known problems, know about terrain traps, etc. and you will massively reduce your risk. Not to 0..
Over this post sequence your argument can be summarized as:
"avalanches are very predictable"
therefore victims are "[making] huge mistakes" or "[failing to make] good decisions", "completely dumb", or "stupid".
But your text has some additional words: "massively reduce your risk. Not to 0".
But if avalanches were completely predictable, the risk from them would be zero. So actually you're saying - in a confusing manner - that "avalanches are not completely predictable".
You've created a classic "Motte and Bailey" fallacy. When challenged you can fall back from the strong claim to the more defensible position.
However the argument's conclusion in (2) is entirely dependent upon the indefensible claim in the premise, so it doesn't work.
After all it is free
After all it is free
We are dancing on the head of a pin here.
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Layne wrote:
We are dancing on the head of a pin here.
Indeed
No one argued avalanche risk is unpredictable
Rather the statement was the PWL (persistent weak layers) specifically make snow pack behave in ways that is harder to predict. Even when the risk is known.
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boarder2020 wrote:
......Avalanches are very predictable. Dig a pit,.......
As you're a bit of a quasi academic, I've a diploma in Avalanche Studies, c/o The European Avalanche Academy, and even with that I never really contribute to the "Why's and Wherefore's'" as per this thread and others, as I know that many far more experienced people than me have perished; and there was another guide this week in addition to the one I posted above.
Over the years I've clicked up a fair number and as @Haggis_Trap, been caught in quite a serious one, ironically three or so weeks after that course.
I also will not comment and try to come across as knowing it all for fear of Karma coming back to bite me in the derrière
And I know I've said as much before, so apologies for the old git repeating myself.
But to the subject of snow-pits, of which I suspect I've dug maybe more than most, and have been examined on them thouroughly.
And yes they can be very illuminating, however I've also seen them give a very false representation of what lies beneath.
When we were digging pits most days over the course of week and in different locations, with other students digging theirs close to ours the results could differ dramatically, in one instance there were about four pits (dug just below P2 La Grave) in nigh on a horizontal line spaced circa 25m apart and where 50% might have reacted to a classic tap test with a shovel the others refused to budge, even though there was an obvious dodgy layer after having done a finger test, when I asked what might the reasons be for this, the examiners were not 100% in agreement but the geography of the slope they said could have a lot to do with it, in how concave/convex it was at ground level but not obviously showing on the surface.
So there's something for you to chew over.
There is something quite unique about this season and there's still stuff sliding on normally stable slopes.
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