How tight are safe trees? What is "near treeline"? Fat skis safe? How deep to effect?

Here are 4 questions that have come up amongst my touring partners and I:

What is "near treeline" in an avi forecast? Around here treeline is usually 11.2-11.8 depending on the aspect and the mountain. Is 11 near treeline or below treeline if the treeline is 11.7 and the valley floor is 10.3? What if the ridge is at 11 at the local treeline is 11.8?

Have the advent of fatter and fatter skis led to a reduction in slide danger to the fat ski skier? I remember reading that paper that showed stress iso lines vs depth for a skier... but does having much fatter (and fun shaped) skis change that? How much? (obviously it depends on the snow consistency...)

What is the depth where skier effect on a weak layer can be considered "low to negligible"? I was taught that it is generally 2m+ and that a "bridge block" test can be performed to confirm the general isolation. Obviously snowpack depth variability and other spatial variability factors come into play as well as the consistency of the upper snowpack (thus the need for testing and taking uncertainty into account), but I was also told 1m by one of my ski buddies. Obviously, dropping cliffs changes the dynamics etc, but how does ski width per the question above affect these numbers? How were they generated? Statistically (as Ian McCammon did in his analysis leading up to the "lemons" system), theoretically, or experimentally?

The old adage "If the trees are open enough to ski, then they are open enough to slide." Who said that? What was it based on? When was that statement made? Was it in the days of 230 DH boards? Volkl Snow Rangers? I can ski incredibly tight trees with my "fun shapes." How tight is tight? Discuss...

Pardon me any typos... I'm buzzed on sake...

Near treeline
Its got a little to do with elevation but as you note, it also has everything to do with local terrain. Its as you say, near treeline. This isnt rocket science :)
Ask yourself, is where you are in the trees close enough to treeline that the snow conditions might be different where you are? Its a judgement call I think on where you happen to be taking into account the recent weather conditions.
ie have the winds been 80mph and creating wind slabs really far down the slopes?

fat skis
if we kept everything the same, sure id say fat skis make it much safer
but with fat skis, and fat skins come an increased access and ability to ski more crazy\further out\deeper stuff. people might be more aggressive and ski more aggressive terrain. so i dont think its so easy as to say fat skis are safer without realizing some of the other factors of fat skis on skiing.

as far as the depth
it depends
i dont think there is a good answer other than realizing any answer would be a rule of thumb. The important thing here I think is to ask yourself this question when making a decision.

Trees sliding
No idea where it originated, but ive heard this too.
I think the point with this statement is that there still exists the possibility it can slide, much like the possibility exists that a completely open 25* slope can slide. Other than that, Id still treat skiing trees in avy terrain with similar caution as Id treat skiing in avy terrain without trees. While the chances of it sliding are probably less, the consequences are also probably much worse.

so yea, the answer to everything is
It depends. :)

i think you're looking for a safe, but fun route to ski. good start.
you need to really educate yourself. start with this book:
Bruce Temper's "staying alive in avalanche terrain" is kinda the bible.

you'll soon learn that snowpack, and avalanches, are incredibly complicated with hundreds of variables combining into infinite conditions that may or may not be hazardous.

i'm no avi expert, and from the east coast- so i have much less overall avi experience- but some.

my buddy triggered a small slide on a steep, tree strewn pitch at mad river glen once that carried me (above him- it fractured above as a small soft slab) into trees below. :eek: definitely a first for me on the east coast.

fat skis reducing slides? probably marginally at best. if a slope is unstable enough to go- a skier weighing 130-200lbs is enough stress to push it over in most cases. i would take anything 'bout fat skis with a grain of salt.

trees can act as two things:
anchors
points of concentrated stress

like rocks, they act as anchors for snowpack. however, avi's are often triggered between trees/rock outcroppings (and can often "jump" these anchor areas when a slab goes) furthermore, trees are a variable; the snow in and around trees can be significantly different than in exposed areas due to exposure to sun, acting as wind-fences (and thus, concentrating snow/loading the area), etc. so trees are by no means safe from avalanching.

if you look at pics of avi's, you'll see that these points of anchor/stress are kinda the connect-the-dots of crowns/fracture lines. with this in mind, being uphill of trees/outcroppings is generally a safer zone than below.

it doesn't take a lot for a slope to go- and even a small slab in a confined area can really really fuck you up.

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Originally Posted by ono

i think you're looking for a safe, but fun route to ski. good start.
you need to really educate yourself. start with this book:
Bruce Temper's "staying alive in avalanche terrain" is kinda the bible.

you'll soon learn that snowpack, and avalanches, are incredibly complicated with hundreds of variables combining into infinite conditions that may or may not be hazardous.

i'm no avi expert, and from the east coast- so i have much less overall avi experience- but some.

my buddy triggered a small slide on a steep, tree strewn pitch at mad river glen once that carried me (above him- it fractured above as a small soft slab) into trees below. :eek: definitely a first for me on the east coast.

fat skis reducing slides? probably marginally at best. if a slope is unstable enough to go- a skier weighing 130-200lbs is enough stress to push it over in most cases. i would take anything 'bout fat skis with a grain of salt.

trees can act as two things:
anchors
points of concentrated stress

like rocks, they act as anchors for snowpack. however, avi's are often triggered between trees/rock outcroppings (and can often "jump" these anchor areas when a slab goes) furthermore, trees are a variable; the snow in and around trees can be significantly different than in exposed areas due to exposure to sun, acting as wind-fences (and thus, concentrating snow/loading the area)

if you look at pics of avi's, you'll see that these points of anchor/stress are kinda the connect-the-dots of crowns/fracture lines. with this in mind, being uphill of trees/outcroppings is generally a safer zone than below.

it doesn't take a lot for a slope to go- and even a small slab in a confined area can really really fuck you up.

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You hear that, summit? You should really educate yourself. You can borrow my tremper until you buy your own. :D

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Originally Posted by ono

i think you're looking for a safe, but fun route to ski. good start.
you need to really educate yourself. start with this book:
Bruce Temper's "staying alive in avalanche terrain" is kinda the bible.

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Read it years ago... Tremper is a smart smart smart man. I tried to get him to come talk at an rescue seminar once but we couldnt afford him. I still consider The Avalanche Handbook 2nd Ed (now reading the 3rd Ed) to be the REWAL bible. This isn't supposed to be a low level discussion, but a high level discussion perhaps questioning the adages we were taught to follow without question.

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fat skis reducing slides? probably marginally at best. if a slope is unstable enough to go- a skier weighing 130-200lbs is enough stress to push it over in most cases. i would take anything 'bout fat skis with a grain of salt.

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this is your engineering background talking here? its about concentrating on the weak layer or damint pechelman can talk clearer i think. bugt anyways if you can spread the applied force over alarege are then the weak layer cfan support a larger total force being applied by the skier before it fails... also depth attenuates it in general thus the other question

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trees can act as two things:
anchors
points of concentrated stress

like rocks, they act as anchors for snowpack. however, avi's are often triggered between trees/rock outcroppings (and can often "jump" these anchor areas when a slab goes) furthermore, trees are a variable; the snow in and around trees can be significantly different than in exposed areas due to exposure to sun, acting as wind-fences (and thus, concentrating snow/loading the area)

if you look at pics of avi's, you'll see that these points of anchor/stress are kinda the connect-the-dots of crowns/fracture lines. with this in mind, being uphill of trees/outcroppings is generally a safer zone than below.

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I'm not talking about the classic "strangeness" of those two isolated trees on the slope being the beginning and ending points of fracture lines (which is generally due to horizontal TG inducing faceting creating weak points rather than localized wind deposits increasing stress), but dense DENSE trees. I first hear the adage I mention back in 2003 after KC Ratcliff died in glades during extreme danger. But 2002 95mm underfoot was considered fat FAT. Yes there was the Spatula but it was unrecognized and undevalud! The Explosive was the powder ski of the era.

A year or two later when I [picked u[p my Spats, skis that were no fun to ski became fun and trees that were unskiably tight hithertoo were now skiable! Now I have Lotuses and EHPs and the Spats are my bnackiup skis!!!!

Thus my questionm on the subject.

NOW DRINK WITH MIE! http://www.japancentre.com/images/it...ekisheishu.jpg

Pechelman nailed it with his description about 'near treeline' I think.

I have heard that weak layers deeper than 1m can't be easily triggered by a skier. However, the image in my head as I type that is of an inbounds slide at Whistler earlier this year, skier triggered with a 3m crown I believe. I suppose like with all avy stuff, there are just shades of grey.

I also remember being told in an RAC that climbers trigger slides easier than skiers, due to the deeper snowpack penetration from walking versus skiing. Could be true I suppose. I can also see the opposite being true and I doubt there's any hard data on it...

Check this slide out. These trees are thick enough that I wouldn't expect or be worried about a slide in there

http://avalancheinfo.net/Parks/Glaci...Accidental.JPG

^^^
where are the tight trees?

that's way open by CO standards. :D

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Originally Posted by Wiilbert

Pechelman nailed it with his description about 'near treeline' I think.

I have heard that weak layers deeper than 1m can't be easily triggered by a skier. However, the image in my head as I type that is of an inbounds slide at Whistler earlier this year, skier triggered with a 3m crown I believe. I suppose like with all avy stuff, there are just shades of grey.

I also remember being told in an RAC that climbers trigger slides easier than skiers, due to the deeper snowpack penetration from walking versus skiing. Could be true I suppose. I can also see the opposite being true and I doubt there's any hard data on it...

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well thats more3 logical because the diference is bigger

its the same as ice... anyone knows that you if you lay down on thin ice, spreading out your weight, thinner ice can support you easier than if you standon it.

similar theory for both deep layers and fat skis. with deep layers, the would be flanks, crown, and stauchwall support you and help spread out the force over the weak layer... thats the whole theory behind a brdige block test

similarly, a fat ski helps spead out the force you the skier are applying and keep the effects less the deeper you go so t he theor ywould say... but how quantifiable is this?

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Check this slide out. These trees are thick enough that I wouldn't expect or be worried about a slide in there

http://avalancheinfo.net/Parks/Glaci...Accidental.JPG

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^those trees are so thin that i wouldnt assign them much credability as anchors on any day!1!

for the sake of the discussion... here is the deadly avalanche i mentioned before (remember it was an black day during the blizzard of march 03)

http://avalanche.state.co.us/NR/rdon...e_03202003.jpg

but I'm asking now, what about those trees lookers right and uphill that are much thicker... those are skiably fun now with fun shape skis... does the adage apply still?

I'm going to sleep now. i'm losing coherency

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Originally Posted by Summit

this is your engineering background talking here? its about concentrating on the weak layer or damint pechelman can talk clearer i think. bugt anyways if you can spread the applied force over alarege are then the weak layer cfan support a larger total force being applied by the skier before it fails... also depth attenuates it in general thus the other question


I'm not talking about the classic "strangeness" of those two isolated trees on the slope being the beginning and ending points of fracture lines (which is generally due to horizontal TG inducing faceting creating weak points rather than localized wind deposits increasing stress), but dense DENSE trees. I first hear the adage I mention back in 2003 after KC Ratcliff died in glades during extreme danger. But 2002 95mm underfoot was considered fat FAT. Yes there was the Spatula but it was unrecognized and undevalud! The Explosive was the powder ski of the era.

[/IMG]

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no engineering background- more common sense. big, fat skis allow you to float, not penetrating as deeply- yes. and yes, they distribute a load more broadly. but again, i would say this is marginal in the grand scheme of things. are two guys straightlining a questionable slope safer than doing figure 8's down it? ostensibly, yes. but it's a basically a fucking moot point, at the margin.

realize that i mentioned the microclimate created in/around trees is a separate issue from the stress concentration points caused by a faceted layer.

the tighter the trees, the more anchors. doesn't take you out of harms way. sorry if i saw relatively basic questions, and attempted to answer- or more accurately, point you toward the answer. didn't realize i was talking to the liquid-courage avi guru who basically had the answers to his own questions if he could only piece it together coherently...:nonono2:

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Originally Posted by ono

are two guys straightlining a questionable slope safer than doing figure 8's down it? ostensibly, yes. but it's a basically a fucking moot point, at the margin.

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It isn't a moot point, actually.

My boss skis with two guys, one of whom is a pretty tele skier, and the other is an alpine skier who skis "heavy."

The alpiner gets slid about 10x more, on the same terrain, such that they'll let him go first or they'll wait until they're out of the slide path before he gets to ski.

Dumb question (I am always afraid to pipe in on this stuff b/c I'm so ignorant) but are lower-weight skiers really less apt to trigger a slide than heavier skiers or is the effect of a skier's weight rather negligible all things considered. When does "weight" become a real consideration?

Is the type of skis they are using equally negligible?

These just seem like minor factors compared to issues with the snow stability itself...at least that what I've garnered in my readings here.

I should probably shut up and just read that book that was recommended above.
:)
Sprite

My takes on your Qs

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Originally Posted by Summit

What is "near treeline" in an avi forecast?

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Relative to the level of treeline, but the critical factor IMO is the affect of wind. Well below treeline or very sheltered areas there will generally be less wind effects, primarily of wind slab development. Thats generally what is critical about near treeline - wind.

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Originally Posted by Summit

Have the advent of fatter and fatter skis led to a reduction in slide danger to the fat ski skier?

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NO - in my view they have led to greater slide danger because more terrain and snow conditions are approachable. With the old skinny skis wind effected snow would eat most skiers alive, so they'd stay away. Fat skis have made more wind effected and deeper snow skiable for the avg joe leading them into dangerous conditions more often.

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Originally Posted by Summit

What is the depth where skier effect on a weak layer can be considered "low to negligible"?

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Depends on how reactive the layer is and the composition of the rest of the pack. But my gut feeling is more than 2X the skier penetration - ie if your skis or penetrate 2' then 4' deep.

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Originally Posted by Summit

The old adage "If the trees are open enough to ski, then they are open enough to slide." ... How tight is tight? Discuss...

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If there is any space then the snow could slide. Of course a 1' wide slide is unlikely to take you anywhere, but a 4' wide slide could take you down into the trees and break you. Trees are NOT a silver bullet for avy prevention. Only slope angle is a silver bullet. Of course generally wind has a lot less effect in the trees so you are less likely to see wind slab formation and therefore lower likelihood of slab avis.

I saw a slide in some VERY tight trees in Jackson this year that really made me rethink my opinion of what tree anchors do. The trees were north facing in Mail Cabin and probably tipped up about 35ish degrees. The fracture line ran about 100 yards and started in trees too tight to ski. It easily could have been one of those days when you decide to bail into the trees because everything else is sketchy. All the debris deposited into the terrain trap creek bed.

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Originally Posted by ono

sorry if i saw relatively basic questions, and attempted to answer- or more accurately, point you toward the answer. didn't realize i was talking to the liquid-courage avi guru who basically had the answers to his own questions if he could only piece it together coherently...:nonono2:

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Oh for Pete's sakes! You came in assuming I knew very little, told me to go read a book, and now are accusing me of being a reckless expert??? :rolleyes: :rolleyes: I don't have all the answers, but I will argue my position. I was looking for a good debate on these topics, not a personal fight, so lets try and start over on the right vein:

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Originally Posted by ono

no engineering background- more common sense. big, fat skis allow you to float, not penetrating as deeply- yes. and yes, they distribute a load more broadly. but again, i would say this is marginal in the grand scheme of things. are two guys straightlining a questionable slope safer than doing figure 8's down it? ostensibly, yes. but it's a basically a fucking moot point, at the margin.

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First, let me be clear on one thing, I'm not trying to argue fat skis should be used as a rationalization to ski questionable lines. This is supposed to be a more analytical discussion than "TGR sez its cool cuz I have fatties!"

You sounded confident, just wanted to know what your basis was. You make some interesting points but as long as we are both still speculating here, I'd like point out that when you combine a great number of conditions together I think it can matter, especially under certain conditions and *potentially* over time.

Consider the multiple factors that we use to lower chances of trigger. We can choose a more modest descent of a given line:
"Lets not hammer that windpillow. Let's not take that little rock drop. Let's avoid that spot that looks thin. Let's ski the left side of the run because it looks about 5 deg lower angle."
Each of these microdecisions reduce chance of trigger by some significant amount while none are a guarantee on their own (or even in concert). I am thinking that fat skis offer similar reduction in chance of trigger as some of the user choices I mentioned.

Like squatch says above, skiing style can have an affect. To answer Snowsprite, yes, skier weight has an effect on snowpack loading for sure.

OTOH human factors could easily negate the "fat ski bonus." As pechelman and smitchell astutely point out:

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Originally Posted by pechelman

with fat skis, and fat skins come an increased access and ability to ski more crazy\further out\deeper stuff. people might be more aggressive and ski more aggressive terrain.

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So I was interested to hear his general point on that subject and tend to agree with him that:

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Originally Posted by pechelman

if we kept everything the same, sure id say fat skis make it much safer

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I'd think one of the biggest times funshape and fat comes into play is when the width keeps the skier on top of what would have otherwise been a breakable crust.
Otherwise, just consider that, not being on 230DH boards, we are no longer hop turning down every power field in site. There's a shock(load)er for ya! ;)

I am going to wager that even a 30mm difference underfoot is not really going to have any effect on whether the skier triggers an avi or not. Does the increased surface area act as a bridge over certain layers, probably, but it's the force of the trigger, not the means, which I associate with kicking the whole thing off. Likewise, would you think that a snowboarder would be safer than a skier on a given line?

As for tree line, I find it very intuitive. Wind and deposition seem to dictate the general area. And come on, you know when CAIC says near and above tree line, exactly where they are talking about. I treat cross loaded open areas similarly.

As for triggering deep slab instabilities, I've always learned to be concerned with the top 2m, but there have been instances this year that just have me really uncertain about skiing even a spectacularly bridged pack. EV #2 slid on a 1mm layer 7' down. I have been musing that when there are persistant deep slab instabilities present, you have to be extra cautious on your upper pack assessment because I think you will have a much greater chance of tickling that hidden dragon through a step down event.

As for trees, I don't give them too much leeway although I do seek them out or ski close to them at times where I may feel a bit hesitant in an open area. It's the pack in the trees that gives me confidence, not the presence of trees themselves. I tend to find, overall, a much more stable pack in dense trees. Since they are protected, the pack goes through a lot less cycles than exposed slopes. I have a couple lines that I regularly ski that hold deep cold snow through late April.

Finally, saki affects your ability to make safe decisions in the backcountry.

back to the ski width issue thing
ive had a little offline talk with upallnight about this and his new acquisition of dp138s.
maybe he can chime in here, ill go ahead and forward him this thread.

anyway, I also recently watched sinners the other day. Everyones on Skinny skis, in the range of 70-80'ish mm. The biggest ski in the whole movie is a g41. Seeing how they make that look bottomless, and the way the rebound in and out of the snow so much, I really do believe that a skier on fatter skis with a smoother more surfy skiing style places much less stress on the pack that the former.

The way Doug Coombs used to describe a skiing turn as "Float & Sting" really resonate here to me. On G41s, that sting portion of the turn is almost like a mini bombhole. Id think youd be more prone to trigger deeper instabilities.

With the Sting portion of the turn on a 138, if one skis them smoothly and not slashing, its really more of a dead feeling surf and the only rebound comes from your body flexure and extension. Id think though that youd now be more likely to trigger instabilities in the upper pack, even if you're now so spread out over much more area, just cause its all concentrated in the upper layers. ie, while you arent penetrating as far into the pack and you're bridged over that, you're also now bridging over a much shallower depth and a lot more stress is thus placed there on those upper weak layers. maybe?

trade off as Im thinking about it right now
G41s = more through the thickness pack stress
138s = more shear stress in the upper parts of the pack

i really do think though that with the right technique, skiing with fatter skis can definitely be safer. Additionally, fatter skis give you a lot more floatation, and thus speed, so you can effectively ski much more mellow terrain that might otherwise bog down a skier on G41s.

Sake is delicious and can be a safe and good decision.

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Originally Posted by snowsprite

Dumb question (I am always afraid to pipe in on this stuff b/c I'm so ignorant) but are lower-weight skiers really less apt to trigger a slide than heavier skiers or is the effect of a skier's weight rather negligible all things considered. When does "weight" become a real consideration?

Is the type of skis they are using equally negligible?

These just seem like minor factors compared to issues with the snow stability itself...at least that what I've garnered in my readings here.

I should probably shut up and just read that book that was recommended above.
:)
Sprite

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Sprite, weight has plenty to do with stability. Think for example, of deep seeded instabilities. We're dealing with layers from as early as October here and the majority of fatalities in Western Canada this year have involved these deep weak layers. These layers are near impossible for a skier to trigger, however there have been plenty of size 1 or 2's that have put enough stress on the snowpack to trigger size 3 and 4's. Also, these deeper layers are triggered by cornice fall, which generally puts a lot more weight than a skier on the slope would.

In summary, send your fattest friend first. If you're the fattest friend, pretend to be selfless and let the 2nd fattest person go first...

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Originally Posted by Wiilbert

http://avalancheinfo.net/Parks/Glaci...Accidental.JPG

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Willbert - was that your doing? We watched that come down from the forcast office across the road - didn't look like fun.

Here is how the CAA defines treeline: the transition area between densely forested areas below and alpine regions above. As I understand it the definition of tree line has less to do with the altitude as it does with the spacing of the trees - which kind of ties into your fourth question Summit. The spacing of trees influences start zones through the ratio of the amount of support a slab has against the number of week spots it has. Thus I don't think that spacing can be considered independently of slope/aspect which are the primary factors in determing an areas propensity to slide.

I've spent most of this winter looking at the issue of the depth of skier effect on the snowpack and so my result indicate that in the Columbia range skier effect is felt down to a maximum of 80cm with very little variance correlated to foot or ski pen. I have no idea how this translates to other snow packs though.

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Originally Posted by pechelman

ive had a little offline talk with upallnight about this and his new acquisition of dp138s. maybe he can chime in here, ill go ahead and forward him this thread.

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so i sent him an email and he came back with this reply although he sounded in a hurry. he said it was fine for me to post this

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Originally Posted by upallnight

just have a minute here, but there is absolutely no doubt in my mind that fat skis lower the avy risk, all else equal. that last bit (all else equal) is a big deal.

why?

well, one could say that fat/cheater skis mean we expose ourselves to more risk (by skiing more vert, more exposed lines, more questionable snow, etc.) and more often.

we also ski faster (= a generally a good thing... i.e., getting out of there quicker...but speed is not universally good as sometimes skiing slow can allow you to step up or off as a slide begins). probably a net positive.

skinnier skis mean more jumping/impact on the snowpack. however, you could also have someone who is really brutal on a snowpack on fat skis. big, slashing turns at speed where you come in hot then 'punch' the turn come to mind (e.g. an inbounds mentality applied to a backcountry snowpack). that doesn't happen when you're skiing slower. overall, it's another net positive to ski fast. i believe even less smooth skills on fat skis are probably less impactful than similar skills on skinny sticks.

distributing the force over a greater area and penetrating less deep are the 2 key parameters, and i think they certainly come out in favor of the fatties.

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Yea, but people ski faster on fatter skis, so I think any extra margin of safety gained by fat boards is negligible.

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Originally Posted by pechelman

back to the ski width issue thing
ive had a little offline talk with upallnight about this and his new acquisition of dp138s.
maybe he can chime in here, ill go ahead and forward him this thread.

anyway, I also recently watched sinners the other day. Everyones on Skinny skis, in the range of 70-80'ish mm. The biggest ski in the whole movie is a g41. Seeing how they make that look bottomless, and the way the rebound in and out of the snow so much, I really do believe that a skier on fatter skis with a smoother more surfy skiing style places much less stress on the pack that the former.

The way Doug Coombs used to describe a skiing turn as "Float & Sting" really resonate here to me. On G41s, that sting portion of the turn is almost like a mini bombhole. Id think youd be more prone to trigger deeper instabilities.

With the Sting portion of the turn on a 138, if one skis them smoothly and not slashing, its really more of a dead feeling surf and the only rebound comes from your body flexure and extension. Id think though that youd now be more likely to trigger instabilities in the upper pack, even if you're now so spread out over much more area, just cause its all concentrated in the upper layers. ie, while you arent penetrating as far into the pack and you're bridged over that, you're also now bridging over a much shallower depth and a lot more stress is thus placed there on those upper weak layers. maybe?

trade off as Im thinking about it right now
G41s = more through the thickness pack stress
138s = more shear stress in the upper parts of the pack

i really do think though that with the right technique, skiing with fatter skis can definitely be safer. Additionally, fatter skis give you a lot more floatation, and thus speed, so you can effectively ski much more mellow terrain that might otherwise bog down a skier on G41s.

Sake is delicious and can be a safe and good decision.

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About the "if its open enough to ski, it can slide" comment, that was told to me as well, but I think its just to keep in mind that it CAN slide, and not view tight trees as an impenetrable fortress of solitude.

I know I don't have half the knowledge or experience of some people posting in this thread, but I think that trees, when combined with other terrain features, can provide safe skiing in times of not so great stability.

why is skiing faster, higher up in the snowpack, more dangerous leeroy?
i guess im missing something

I'm a relative newbie to Avy talk, but one thing that really opened my eyes is witnessing the aftermath of a strong class III - took out "mature timber" that I would have previously viewed as a safe zone. What was interesting is that the trees were probably 50-75 yrs old, so you could say that they were in a protected area to be able to reach that age, but that one event - a 50-100 year slide took 'em right down. So it is kind of like earthquakes or storms, or any "natural disaster" when there is a deep enough pack for a class III, it is not ever "safe", no matter how tight the trees. Maybe there's a stand of 99 year old pines, but they could be blown out next year... anyway, I do think there is something to the "if you can ski it, it can slide" mantra.

On the topic of fat skis, I like the discussion of more stress on upper layers vs. lower layers. It makes sense that in a given turn in a given 2' deep pile of snow, the fat ski will move more snow in the upper layer(s), while a skinny ski will cut deeper through, but maybe not *move* as much snow. Is the trigger really sprung by cutting down to it vertically or rather by applying weight/force above it to a failing point, or both!?!

I submit that the ski width factor is moot because if it came down to how many mm's under foot and the difference between setting off an avi or not, there are a lot more important things you could have spent your money on (like education) besides buying a fun shape.

im not sure anyone here is suggesting that we go out and buy fat skis for safety

i thought we were just discussing what effects different sized skis, skiing styles, and people have on\in\through the snowpack.

edit
and shit squatch
are you exaggerating with your 10X comment?

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Originally Posted by pechelman

im not sure anyone here is suggesting that we go out and buy fat skis for safety

i thought we were just discussing what effects different sized skis, skiing styles, and people have on\in\through the snowpack.

edit
and shit squatch
are you exaggerating with your 10X comment?

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possibly he was, but he's not the exaggerating type.

Granted, they may be operating on a different level of acceptable risk than most people do (same group, same terrain, so they're familiar with each other and managing slides)

it goes back to UAN's comment about skiing the backcountry like it's in-bounds. Trying to make cool slash turns don't help your cause.