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

[covert]

i responded to this rescue from a-basin and en route to the scene my partner and i encountered SS-N ~2m crown maybe 50' across in "tight" trees. skiable trees yes but tight enough that i would not have considered them potentially hazardous. the "extreme" hazard of the day was just that. RIP KC...

[Mofro261]

So since I weigh less I should be ok making slash turns as long as they are done on sufficiently wide enough skis.


as you were.

[MakersTeleMark]

So since I weigh less I should be ok making slash turns as long as they are done on sufficiently wide enough skis.


as you were.

Only if you tele 'cause that spreads out the slash effect which you have to make up for by blasting Welcome to the Jungle on your ipod.

You know where you are?

You're in the jungle baby, and you're gonna die!!!!

[Mofro261]

In the jungle
Welcome to the jungle
Watch it bring you to your
kna-na-na-na-na-na knees, knees


Well I'll be damned,it seems so obvious now.
A not so subliminal message right on my IPOD to only make backcountry slash tele-turns on wide skis at my weight.

[Wiilbert]

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

I am thrilled to report I had nothing to do with that. However, at least the person who started that has managed to get out skiing since mid January, so they have me beat there.

[BenWA]

Stepping back a bit, my feeling is that most of your questions are a bit too focused and zoomed in, and the answers to some of them really needn't (and shouldn't) be considered during decision making... because in reality the differences between fat skis and skinny skis, a fat skier and a skinny skier, 1 m vs. 2 m of snow depth to diffuse skier load, etc. are all negligible when you consider how the scales of all the other possible variables may make the significance of all the variables incomparable, at least practically speaking.

As an example, if a 150 lbs skier and a 300 lbs skier ski the same line exactly the same way on the same exact skis and in exactly the same conditions, the weight difference between them will be a drop in the bucket if both skiers are pushing 2 tons of slough in front of them as they descend. The point is that there are too many other variables of vastly incongruent scales to consider.

What's far more important than worrying about the potential cause and effect of all the little nuances that may impact the stability is INSTEAD worrying about your own decision-making mindset from which you approach a given situation. I find that far too many people try to take a micro-management approach to recognizing stable vs. unstable slopes and in deciding when to ski or not ski a given slope (e.g., this little patch over here is probably safer to ski than that little patch over there, so lets ski it) when they SHOULD be approaching it from a far more conservative perspective, using the least stable slope in the vicinity as the lowest common denominator upon which to base their decision. In other words, they have a tendancy to find reasons why they SHOULD be able to ski a slope, rather than find reasons why they should not.

As humans, we are conditioned to approach problem solving from a perspective of seeking ultimate success in whatever goal we have set in our sights. For example, we WANT to ski that slope and, dammit, we will seek any solution we can to become successful in doing so. Unfortunately, nature doesn't always work that way and sometimes we just have to accept failure by saying "no, not that slope, not today."

In my opinion, trying to use fat skis or tight trees as justification to ski in otherwise unstable conditions can be part of a faulty mindset in decision making. Justification has historically killed many "experts". Remember, justification is the narcotic of the soul. Do your best to curb your addiction.

[jfost]

good points for sure BenWA, but I think it is (or should be) always ok to step aside and dig into the "why" a little. This is how knowledge is made... Summit's drunken opus was headed that way, NOT towards "fat skis are safer than skinny - so let's ski sketchy lines".

I think it is worth parsing out the minutae, because otherwise we may not ever find out why 99 skiers hit a particular slope and it decided to let go on the 100th.

NEED INPUT!

/johnny #5

[leroy jenkins]

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

Because skiing like that is inherently faster, leading to big high g turns, etc. Thats just my guess though, nothing more.

[ono]

i'm in agreement with BenWa's logic here... myriad variables forming infinite combinations of conditions- well, it nullifies the particular benefits/detriments of fat/skinny skis, skier's weight, style of skiing in relation to snowpack instability. i'm done.

[adimmen]

Stepping back a bit, my feeling is that most of your questions are a bit too focused and zoomed in, and the answers to some of them really needn't (and shouldn't) be considered during decision making...

The genesis of these questions had nothing to do with a go/no go decision. They are the product of wandering minds over endless hours of touring and were more theoretical than practical (jfrost hit the nail on the head with his comments).

[adimmen]

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.

This highlights the multivariate nature of these problems. Beyond the obvious effect of layering, the moisture content likely plays a large role. Here in CO our weight probably penetrates deeper in the drier, early season pack than the wetter, spring pack. It still amazes me how much the mind wanders during a long outing.

[summit]

As we can see from the first page discussion, there is consesus on some points of treeline and not on others between the 5 or 6 people who responded to the Near Tree Line question. Is it the tree density? Is it the succeptability to wind? Is it the relative height versus local terrain?

I left the SWAG book at the office... I was thinking that must definitely have a definition for "Near Treeline"

See, I thought NTL was a variety of factors. Without a clear answer, I've been considering (when considering remotely) it versus both absolute terrain height, terrain height relative local terrain highs and lows, and terrain height relative to actual treeline; as I see it, what these things affect are the following variables: not just anchor/weakspot density (tree density) succeptability to wind, but also relative snowpack depth (tends to be deeper higher unless scoured), relative snowfall rates (it snows more higher), and temperature (its warmer lower).

While NTL is a broad term meant to categorize, to me, NTL vs ATL/BTL is a decision factor in that I use the NTL forecast (as well as the rest of the forecast) as information to help determine where I might set my sites on as a touring area for a day and what kind of things I should be on the lookout for based on the forecast until I can make my own determination of the local snowpack.

Ultimately, when you are there, you make the determination of whats actually there, not what some definition says. I guess the answer most relevant to my question would be: what definition does CAIC use? But I couldn't find a definition on their website... thoughts?

[pechelman]

first, i dont think the intent here of the question or discussion of any of this was meant to be used in actual decision making. Really I think this is just an academic discussion. You people thinking that Summit and I are going to make decisions based on how wide our skis are, are pretty silly.

second, on the NTL stuff summit, i think you're being a little over academic here
I really think that the CAIC uses the NTL definition which I tried to describe in my first post and which smitchell33 followed up on. Like you elaborate above, it also has to do with snow depth and temperature to some degree, but really i think its all about wind here in colorado. Again, its not rocket science, theyre just trees. (ok so if i strap a jetpack onto a tree it turns into a rocket, so what )

[summit]

first, i dont think the intent here of the question or discussion of any of this was meant to be used in actual decision making. Really I think this is just an academic discussion. You people thinking that Summit and I are going to make decisions based on how wide our skis are, are pretty silly.

Exactly! The only points that might play into decisions are NTL definition helping me figure out where I might tour on a given day (not what line I end up skiing) or *perhaps* the depth of effect (but not really because there are actual stability tests to offer some idea if you did want to factor it into the decision).

ok so if i strap a jetpack onto a tree it turns into a rocket

We definitely should do this... for avi control or something... it'll be cool!

[Bart T]

heard once that a falling skiier puts the same amount of force on the pack as a one pound bomb. so i pretty much treat avy terrain on considerable days with the same respect as chutes with a big dogleg and a cliff at the bottom -- as no fall terrain. so +123 for fat skis.

as for trees, I go by whether or not there are any branches on the uphill side, if not you're in a slide path. of course, i would rather be there than in some wide open bowl, but I'll keep my safety goggles on - ymmv.

[Conundrum]

Here's my take on fatter skis.

Many slides are propagated from a distance. This means there is a certain weight that will will overcome the tensile strength of a weak layer causing failure. So, the more weight, the more chance of propagating. So fat skis won't make much of a difference if you are propagating from remote trigger sites due to weight on a slope.

Another trigger is breaking through parts of a slab that were "holding" the slab from sliding on an already broken weak layer ie cutting loose a slab on a ski cut or sending something by skiing over a convexity. I think a couple inches of float extra is still splitting hairs unless you are getting those skis up to plane like a ski boat.

I wouldn't base my life or my buddies' lives on "couple weak layers here, good thing I brought the Birdos today".

But it goes back to all depends.

For the depth of concern, it really goes back to knowing the history of the snowpack. There have been some man eaters this season from the pnw over to MT that have 10 foot or more crown faces on some really weak layers. Most people only dig 6 feet or so. If you know of massive loading and some early season hoar, you might take the time to dig.

Trees-no way to be certain. Stuff slides in tight trees too. I like the addage open enough to ski, open enough to slide but it still depends on the snowpack, thermal affects of trees and sun, etc.

My .02 and answer to all of this is to follow general safety rules, know the snowpack and be humble.

[jfost]

...
as for trees, I go by whether or not there are any branches on the uphill side, if not you're in a slide path. of course, i would rather be there than in some wide open bowl, but I'll keep my safety goggles on - ymmv.

this is what I was trying to get at before. The trees with uphill branches *seem* safe, but a 100yr. slide could get you right in the middle of it! Those class 3&4's in the PNW this year are just the animal I fear. I guess it depends on what exposure is above you when you're in the relative safety of trees...

[summit]

I've always used flagging as a warning on where to put my routes, tracks, and safe zones.

I think we are starting to miss the point if one regularly focuses on the potential danger 100 or 500 year events in daily skiing decisions... which are by their nature irregular and extremely rare. You are more likely to have a tree fall on your head unless you seek danger during an activity cycle where conditions are running 100 year slides.

[Lani]

Agreed that conditions for slides that big are generally stupid obvious. It's the gray zones that'll get ya.

[jfost]

I've always used flagging as a warning on where to put my routes, tracks, and safe zones.

I think we are starting to miss the point if one regularly focuses on the potential danger 100 or 500 year events in daily skiing decisions... which are by their nature irregular and extremely rare. You are more likely to have a tree fall on your head unless you seek danger during an activity cycle where conditions are running 100 year slides.

yeah, true enough... the conditions are the first warning. This years Dec. 4th and Jan26th? PNW crusts are the red flags, and caution should be taken accordingly. Most years mature timber would be safe indeed, but by the looks of the downed trees up there - these are at least "75 year" events happening.

But you are right, if we wanted to worry by numbers, we'd all want to re-think driving to the slopes... or eating butter & bacon... or walking across the street without our helmets!!!

[Lani]

Yo jfost: not trying to talk shit, but the really big slides aren't "happening." They happened during multi-day/week-long snow events that featured new snowfall by the meter atop those crusts, then further new snowfall accompanied by warming. Seriously, not trying to talk shit, but that's how the big ones slid in Washington last month. There really wasn't any mystery about it. If you were trying to ski anywhere below slide paths at that time, then you were asking for it.

[lemon boy]

not a particularily valuable contribution to this thread but every time I see it the question that jumps to my mind is:

How safe are tight trees?

[1000-oaks]

This was my first season on Pontoons, and the first season I've kicked off slides - two of them spooky and could easily have been leathal (I stayed inbounds after that first dumb run OB). But I think the unusual snowpack this year was much more of a factor than the fats luring me into questionable conditions.

[pechelman]

having this thread bumped after summit's "Below Treeline Chuting TR" makes complete sense now