Avalanche

[Cannatonic]

Tough year out west. I've always been somewhat skeptical about avy science. It's never a sure thing. Never liked these reports that say "watch out for convex rolls, lens-shaped snow, or certain slabs, etc, etc." As if you can eyeball the snow & pick you way through the minefield all day. That's not pragmatic advice. You can't ski safely in avy terrain under those conditions, you should stay in the trees or low-angle.

https://backcountrymagazine.com/stories ... -traverse/

https://backcountrymagazine.com/stories ... -elevated/

[paulzo]

The real issue is the complexity of the composition of the snowpack. If it were possible to know the composition of the snowpack in precise detail, all the way down to the ground, not just at one point but throughout the area that you are in, then it would be possible to accurately asses the true avalanche risk, which would vary from one spot to another within the area. But that is not possible. A person truly skilled in snow science can dig a pit to expose the various layers and analyze the composition, the crystal shapes, etc., and give a good assessment of risk at that spot; but from that it is all extrapolation, based on experience and probabilities. And of course, without digging the pit you are just guessing. Given that not everyone has the snow science knowledge, and even those who do don't always dig the pit to make the assessment, It's safe to say that quite a few skiers are just rolling the dice.
The only truly safe way, as you say, is to avoid terrain where avalanche is possible. But of course that means you are not going to ski much deep powder unless it is in thick forest, since in deep powder any slope gentle enough to be avalanche proof is too gentle to ski, you just won't move. That nice open steep powder slope starts to look mighty tempting and people succumb to that temptation.
I'm sort of lucky in that what I like to do is multi-day trips and the spring is the time to do them. By the time I head out, the snowpack in the SIerra where I ski has turned isothermic and become pretty thoroughly consolidated, so that the only real avalanche danger is afternoon wet slides on the warmer days - something very easy to avoid. Plus, being a crappy skier, I can't handle the steep stuff anyway!

[Baaahb]

I ice skate on frozen ponds and find it amusing when people express concern over the safety of the ice. One can reliably assess the thickness and safety of pond ice (of course, if one knows what one is doing.) OTOH, one cannot reliably assess the safety of steep snow-covered slopes, as has been demonstrated often. And this is what bugs me about avy discussions...the heuristic traps are substantial and often seem to be exacerbated when people have received avy training. You can mitigate your risk, but you cannot eliminate it...and avy gear only mitigates to a relative extent. The difference between skiing on a low risk day and on a considerable risk day are huge.

[Cannatonic]

>>If it were possible to know the composition of the snowpack in precise detail, all the way down to the ground, not just at one point but throughout the area that you are in, then it would be possible to accurately asses the true avalanche risk, which would vary from one spot to another within the area. But that is not possible.

this is what they call "spatial variability". The east is similar to the Sierra, mostly "marine" snowpack - it's easy for us. Wait 24 hours after snow or major wind loading stops and you're 99% safe. (perhaps the experts don't like this rule because it's too simple and easy to understand?) Continental snowpack can be ruined by one bad layer for months.

We also saw an inbounds avy death at Taos ski area this year which is very rare. I guess I just see these very long, jargon-filled avy reports and I'm questioning the method. I see a layer of arrogance in there. No "expert" knows everything. Any report over 2-3 sentences long is not going to be very useful to the average person. The truth is that experts often die just as easily as neophytes, despite looking out for "spatial variability", "lens-shaped convexivities", etc, etc.

Areas where skiers regularly pack the snow down via skiing are much safer as well, though I never see references to that in avy reports. *edit - I like this graphic from the Mt. Washington rangers, seems like a good attempt to make things clear without extra jargon:

[lowangle al]

I love skiing, but I don't want to die for it. The older I get the less risk I'm willing to take, as I have seen almost all of the scenarios I once thought to be safe were not. I had some great days this past week and I don't think my stoke could have been any higher if I had skied steeper slopes.

he only truly safe way, as you say, is to avoid terrain where avalanche is possible. But of course that means you are not going to ski much deep powder unless it is in thick forest, since in deep powder any slope gentle enough to be avalanche proof is too gentle to ski, you just won't move. That nice open steep powder slope starts to look mighty tempting and people succumb to that temptation.

Paulzo, I agree that if you stay out of avy terrain you miss the best of it, but if you want to ski deep powder on lower angle slopes you just need fatter skis.

[lowangle al]

Spacial variability is something I'm more willing to deal with than a persistant weak layer that could go at any time.

[HBS]

I guess I just see these very long, jargon-filled avy reports and I'm questioning the method. I see a layer of arrogance in there. No "expert" knows everything. Any report over 2-3 sentences long is not going to be very useful to the average person. The truth is that experts often die just as easily as neophytes, despite looking out for "spatial variability", "lens-shaped convexivities", etc, etc.

Areas where skiers regularly pack the snow down via skiing are much safer as well, though I never see references to that in avy reports. *edit - I like this graphic from the Mt. Washington rangers, seems like a good attempt to make things clear without extra jargon:
avy.jpeg

The two problems are that the reports are trying to speak to the broadest audience possible and remain relevant instead of just repeating the same warnings day after day. People may not understand what a wind slab is or how the rose diagram works, so they use text. If they present the same images day after day people get complacent while the danger can be more nuanced. For instance, in Colorado we get "spooky moderate" where the risk of triggering an avalanche is relatively low but if it happens it will step down to deeply buried weak layers and almost certainly kill you. Someone who is ok making their own assessment on other moderate rated days would likely avoid the terrain entirely just because of the risk of large avalanches.

To be honest, if you as a backcountry traveler are unwilling to spend 10 minutes reading a detailed avalanche report (the CAIC has a great discussion page that gets updated every few days) and accident reports then you aren't really taking things seriously so I doubt simplifying things would really work because its easier to dismiss.

[wooley12]

Part of traveling safely in avalanche prone terrain is to know when the talk and when to walk. I paused to chat with this experienced skier and he suggested choosing one side or the other of the slide path to continue our conversation. Reducing the time one is at risk is a part of avoidance.

[1EyedJack]

BIG one on Mt. Shasta a couple of weeks ago.
Shasta: Nthn California, Cascades chain

http://shastaguides.com/blog/

If nothing else, check out pics of Shasta.

[Cannatonic]

epic winter for California! I just read that Mammoth Mtn. set a new record for February snow - you know that means A TON of snow.