Portions of East Vail are Effectively Skier Compacted

[pde20]

I don't know if I agree with the title or not, but figured it was a good way to engage the conversation. I feel only slight hesitation at writing this as I believe that the train has permanently left the station regarding access to and use of east vail by minimally educated or prepared side-country users. Same goes for Berthoud Pass, Loveland Pass, A-Basin side-country and possibly other locales. So, might as well play with whatever interesting aspects are left to see if there is edumacation to be shared. My only concession is to not name specific and commonly utilized names in this zone.

How does a ski patrol define effective skier compaction?

When resorts do compaction work they do it w/ boot packing as opposed to ski compaction. To what depth does a skier effect change in the snowpack, based on different modes of travel/compaction?

Is there only a short window of time (early season) where compaction of whatever variety is a relevant and viable tool? Or, can compaction be used to target specific layers at specific times?

Is there snow science geek literature on this?

In sum, at what point is a line effectively controlled by use?

I understand that the infinite spatial variability of the snowpack makes this an intellectual exercise, so no need to tell me "it depends." Certainly the effects of skier compaction must be relative to the frequency and intensity of storms, loading patterns, slope angle and characteristics (alpine, near tree line, bed surface) etc. But what else is there to be said here?

Applying this train of thought to a specific place seems most informative, so I choose east vail. The only limiting factor i have observed to east vail usage is the closure of the poma, NOT high or rising danger, not midst of a storm, etc. At this point there are few periods of I"d guess greater than 18 hours that the perceived lower consequence lines in east vail aren't getting hammered. By hammered I mean completely tracked out. There are legit moguls in the run out zone at times now. So, that leads me to my conclusion about relatively constant, frequent use of AT LEAST the perceived lower consequence lines, many of which are not thickly timbered.

I started thinking about this as I descended vail pass in my car late last middle of last week (2-3 days after the end of a very significant storm cycle) and observed the full sweep of the bowl in favorable light where I could make out a lot of detail and thought, "jesus H, that looks like china bowl after a powder day."

Summit, if you could illustrate w/ appropriate pictures I"m sure this will be a much better and productive thread

Edit: And thanks for the title substitution....hmmm, actually you can't change thread titles?

[summit]

I don't really agree with the title.

Can skier compaction help in the backcountry?

As you noted, it's pretty hard to quantify. I'm not going to try! It's right on the same level of "do tracks indicate stability in the backcountry?" (Although someone did bother to quantify that...)

The answer is the same: Sometimes... maybe... possibly to some extent... but you can't be sure and you'd better not trust it!


Image by Jamie Robertson

WHAT? WHY?

IMO "Skier compaction" can be best described as: Disruption of weak layers by ski tracks.

If you disrupt a weak layer sufficiently, you eliminate it's ability to propagate a fracture and release a slab avalanche.

Evaluating compaction in places like East Vail, BP, and other such "high traffic" ares etc is a multifaceted (ha!) problem beyond concluding: "my line has been douched!"


Are those moguls and slide debris? Image by Andrew Parker

WHY SKIER COMPACTION IS VARIABLE IN THE BC

So you would ask: are we truly disrupting the weak layer? Skiers may not penetrate to the weak layer while skiing. A weak layer that was buried under the new storm snow, but which was stronger than the load, might not be disrupted even though an area is "tracked out," and yet didn't slide... yet. It doesn't even have to be a lot of new snow to shield a weak layer. It could be a little wind slab.

Take that layer and drop new snow load on it, or have the type of weak layer that may get weaker after the storm, and now that layer that was skied over but not disrupted, has become reactive!

Do you think we ever "skier compact" the depth hoar in the side country? Of course not. This is why patrol has to side step when it is thin and why Silverton and Aspen bootpack. You have to get penetration to disrupt layers of concern. Many inbounds areas never eliminate the deep instability danger!

EMERGING TRENDS: NEW EQUIPMENT AND COMPACTION IN "HIGH TRAFFIC" SIDE COUNTRY!


A recent picture from your favorite backcountry access gate

East Vail might see 400 tracks on a very busy day... but that is spread out over an acreage that approaches the Vail inbounds acreage depending upon where you draw the boarders! It wasn't always this way! We've all watched traffic go up and up. I've seen moguls on Tele Line fer heaven's sakes! There didn't used to be enough tracks to think about skier compaction at all!

There is undoubtedly a link between the increased traffic in the backcountry, and the wide acceptance of fat and rockered skis that make powder skiing a breeze for any bro bra. With the advent of these fat skis, we are compressing less snow (our tracks are not as deep), and thus we have even less chance to disrupt the weak layers. (And yes, this is a concern to ski patrollers for certain inbounds areas!)


The Revolutionary Gear Hero

This is a topic of discussion amongst avalanche professionals, but the research is thin at this time (and hard to quantify). I've heard some interesting and sensible new ideas based on anecdotal observations, but I'm not supposed to repeat them yet...

[Crampedon]

Wtf is that second to last pic, from WWII or something? C'mon!

[summit]

That's Chilkoot Pass, 1898, during the Klondike Gold Rush

(for some reason the winky face didn't show up)

[DasBlunt]

Thanks Summit.

The premise of this thread seems somewhat flawed. I would not want any of our compromised reading comprehensive crowd to get the wrong idea. Maybe worthy for nukes? But, they most likely do not come in here anyways.

[Shredhead]

When resorts do compaction work they do it w/ boot packing as opposed to ski compaction. To what depth does a skier effect change in the snowpack, based on different modes of travel/compaction?

Is there only a short window of time (early season) where compaction of whatever variety is a relevant and viable tool? Or, can compaction be used to target specific layers at specific times?

Is there snow science geek literature on this?

Highland's does extensive boot packing preseason. Mac thinks that breaking up the lower layers to a depth of 3-4 feet and getting air into them, consolidates the snowpack? I saw a paper on it once, but not sure where?

[gunit130]

oh yeah cool bro. so ya saying east vail is safe cause when people ski there and make tracks and shit the snow packs down and its safe. cool be there tomorrow!

[Name Redacted]

The professor near a-basin had about 100 tracks early this season. Cdot bombed it (with a shitton of explosives) and it went HUDGE! Skier compaction is better than nothing but definitely not indicative of stability.

[volklpowdermaniac]

As much as people do access side country stashes, I don't think the levels (however high they are perceived to be) are even close enough to create a significant stabilizing effect on the snow pack in that particular area. I think the only place this occurs is in bounds avalanche terrain, where patrol consciously leaves terrain open during storms and whenever else they can (albeit after mitigating risk to some extent) so the public, served by lifts, can act as a control tool, which they definitely do. As much as we think the side-country is being infiltrated by the masses (and by our standards it may be) it seems that you would need significantly more traffic (ie only the amount that a lift allowing for laps over and over) for SIGNIFICANT stabilization results.


Obviously each track down a path has the potential to break up weak layers, but it also has the potential to bring the path one step closer to the trigger point.
</stream of consciousness>

[khakis]

When resorts do compaction work they do it w/ boot packing as opposed to ski compaction.

Doesn't Loveland "ski pack" the avy chutes every year? Or is sidestepping up the whole thing just a way of hazing the new guys?

(a little overlap with VPM's comments below...)

Like Summit said, the idea is to disrupt the connectivity of weak layers to the rest of the snowpack...that's easy...you send 5 guys bootpacking up a 1-foot deep snowpack, and when they are done, the resulting (1-inch deep) snowpack will be completely consolidated. Aint goin nowhere. But only for that portion of the snowpack directly under the boot prints.

Seems like the real issue is determining the minimum intensity to make a difference. If you take 5 guys out to a couloir in early season and everybody makes wide turns all the way across the coulie, each taking a different track, and the snowpack is such that there's no facets next to the ground and each ski track compresses all the way to the ground, maybe they have effectively disrupted the connectivity of any weak layers and that run will be safe after the next 6 inch event (if no surface hoar develops...and if no depth hoar develops, and if the 6" isn't wind loaded or all deposited in a cornice at the top...etc etc etc). Seems to me that the above scenario would result in a pretty stable base.

(Never skied EV, take the rest of this as pure conjecture)

Now take those same 5 guys and have them schralp EV with a 3' snowpack with all kinds of weird sh1t already developing and you're spitting in a lake trying to raise the level. What if it were 50 guys? Or one small chute? Or a 2' deep, first snow of the year, non-wind-affected, with anchors?

In my mind, it seems like the only way for the snowpack to be significantly (hate that word in general conversation) stabilized by skiing, with any level of predictability or confidence, it would have to be done much more purposefully--in both a spatial and temporal sense--than just constant schralpage by every goofball who can get to the top. Further (and unfortunately), it seems also, that the sheer intensity and uneven distribution of the skier disturbance could actually take the snowpack in the opposite direction, making the snowpack actually more unstable than similar slopes that haven't been packed down. I assume fresh fluffy snow insulates better than snow that's been skied...does this mitigate the generation of depth hoar during a very cold cycle? Lot of variables, but it seems like (of course) with the right knowledge, and the right manpower, that directed use could be used as a control technique...

[pde20]

Thanks Summit.

The premise of this thread seems somewhat flawed. I would not want any of our compromised reading comprehensive crowd to get the wrong idea. Maybe worthy for nukes? But, they most likely do not come in here anyways.

You are right in so far as there are obviously folks w/ reading comprehension issues already posting in this thread.

oh yeah cool bro. so ya saying east vail is safe cause when people ski there and make tracks and shit the snow packs down and its safe. cool be there tomorrow!

What was presented was a hypothesis and a bunch of questions meant to confirm/refute it. Not my responsibility to notdiscuss something in an intelligent fashion in order to cater to gunit or his ilk, like I said, they are out there regardless of what I do. Take Summitt's recent snow pit thread. Great thread, nuanced discussion, but if you are a knee jerk type or incapable of processing words and complex concepts than all you see is "snow pits are worthless."

Thanks Summit, Shredhead and others for putting some mental muscle into things. I've actually been impressed recently w/ some of the discussion in this little corner of TGR.

[gunit130]

just trollin man, chill

[khakis]

Patrollers of all persuasions participate, there is no hazing involved.

oops forgot the smiley...that part was a joke

[MakersTeleMark]

http://avalanche.state.co.us/acc/acc...ident=20050520

[bodywhomper]

I know very little about the munter method, but this is included in its decisionmaking process.

[pde20]

http://avalanche.state.co.us/acc/acc...ident=20050520

IMHO this accident demonstrates that an isothermal pack is a completely different animal and ALL tactics for controlling a layered, mid winter pack need to be reassessed once the snowpack transitions. So, this example is no more or less relevant to the discussion of skier compaction/disruption than it is to explosives, wind fences, cornice cutting, etc, etc.

This A Basin accident was scary, but I saw the same thing at Park City once. Jupiter Bowl is diretcly under a chair lift, gets skied to the point of being a mogul field, heavily controlled all winter. In April it had transitioned and the snow safety director knew that the concern was free water at the bottom of the pack and a bed surface of essentially a slab of rock. So, one well placed shot in the middle of a mogul field on a warm morning and the whole bowl went. Quite a weird site to see a field of moguls liquify and move down slope.

In both examples, the circumstances of the wet slide don't tell us anything about the effectiveness, or lack thereof, of tactics used on a mid winter snowpack.

[Name Redacted]

IMHO this accident demonstrates that an isothermal pack is a completely different animal and ALL tactics for controlling a layered, mid winter pack need to be reassessed once the snowpack transitions. So, this example is no more or less relevant to the discussion of skier compaction/disruption than it is to explosives, wind fences, cornice cutting, etc, etc.

This A Basin accident was scary, but I saw the same thing at Park City once. Jupiter Bowl is diretcly under a chair lift, gets skied to the point of being a mogul field, heavily controlled all winter. In April it had transitioned and the snow safety director knew that the concern was free water at the bottom of the pack and a bed surface of essentially a slab of rock. So, one well placed shot in the middle of a mogul field on a warm morning and the whole bowl went. Quite a weird site to see a field of moguls liquify and move down slope.

In both examples, the circumstances of the wet slide don't tell us anything about the effectiveness, or lack thereof, of tactics used on a mid winter snowpack.

Agreed, people always point to the a-basin slide and forget that it was a freak accident cause by extremely warm temps. I rode that run the day before and sunk up to my knees in slush. The day of the slide I was riding my mountain bike a few miles away in a tshirt and shorts. It was a very fast warmup that spring. They learned a lot from it though. The warm weather in that case outweighed the effects of skier compaction because there was basically a river flowing under that skier compacted snow.

I think that skier compaction has more to do with multiple variables like: When did the skier ski that line? Has the temp or weather changed since? Did they make hard ski cuts and jump turns or just a few really fast drawn out turns? Ect. ect......

[SickerThanYou]

oh yeah cool bro. so ya saying east vail is safe cause when people ski there and make tracks and shit the snow packs down and its safe. cool be there tomorrow!

I have a GoPro and jacket with Recco. One time i skiied on Loveland pass. Can I come?

[goldenboy]

Crested Butte has also had a program for as long as I can remember. My first year here, 93-94, they offered tours into the North Face early season when it was still too thin to open- the tours were mostly a way to get some tracks out there.

Much more effectively, they have also had a packing crew where 80 hours= a season pass. The last few years they switched from sidestepping to bootpacking.

I hope they took some before and after pictures this year, I think they would really drive home how effective the program is in a continental snowpack. There was a 50' wide section between routes on Big Chute and paradise Cliffs that never got packed- it was the only thing in the headwall area that slid during our 5' pre-christmas storm. Under the Silver Queen in the Forest area, they only packed the open area directly under the chair, not the adjoining glades. The glades slid, the packed area under the chair did not. They never really got out to the North Face, and huge sections out there slid as well.

As for EV/BP/etc., I doubt that the ski penetration is really deep enough to significantly effect the stability in a positive way. That's why most packing programs have switched to bootpacking rather than sidestepping. I doubt it hurts, though, except for maybe giving a false sense of security.

[Name Redacted]

Yeah, let's all go bootpack EV!

Seriously, that makes a lot more sense though, especially since most of the ppl skiing EV are on +130mm waist skis... Doubt that does much for compaction, as has been discussed in the past.

[goldenboy]

Yeah, let's all go bootpack EV!

Ha! Funny thing is, when I read that, I was reminded of a wingnut friend of mine who really did try to self-compact a favorite tree shot of his in the Monarch pass area. He was very proud when a bunch of stuff slid, but not his little line. Still sounds like a dangerous and dumb idea to me, not to mention WAY too much work to go sidestepping in the backcountry all early season.

[BFD]

I'm a little lost on the concept. Isn't one purpose to keep the snow from blowing away. I understand getting rid of early season layers that may become deep instabilities. What about new snow old snow interface. Do you bootpack every storm? Somebody has to make first tracks. Seems like people have died at ski resorts that have alot more skier traffic than most backcountry areas.

[Puffin]

Maybe it can help with soft slabs....a little.

What about hard slabs? Deep slab instability?

I'm gonna make this claim without doing the research, but I am fairly sure that every documented fatality from china wall/mushroom and from pitkin bowl to gen-x has been from hard slabs.

Skier compaction doesn't do a thing for that.

In addition, what about every time it snows, and reloads a few feet of snow in a single day? There's a reason why Blue sky (which is effectively skier compacted usually within a day after the storm) gets blasted before you can shred it. Even if it didn't snow for 6 weeks, melt thaw every day and EV got as skied out as northwoods, as soon as it snowed again. What BFD just said was right on...

IMO anyone that thinks tracks matter when it's deep (which is basically whenever the it snows in EV) is a not educated enough to be out there. And I'm sure lots of the dumbasses I see out there think that, so this thread is a good thing. It just snows way too much there. I've had waist deep when the mountain has just a few new inches...

[bodywhomper]

I'm a little lost on the concept. Isn't one purpose to keep the snow from blowing away. I understand getting rid of early season layers that may become deep instabilities. What about new snow old snow interface. Do you bootpack every storm? Somebody has to make first tracks. Seems like people have died at ski resorts that have alot more skier traffic than most backcountry areas.

from best that i can tell, this is about 2 different, but related subjects: the effects of early season compaction, i.e. stomping down a very shallow and weak snowpack, and the effects of slopes that get skied-out with a deeper snowpack.

earlier in this thread, i mentioned munter's methods because it is the only place where i've heard of actively using the fact that a slope is tracked-up as part of the decisionmaking; a slope with multiple visible tracks would result in a reduction of the risk that the slope would avalanche. I find his "multiple tracks" thing interesting. Apparently, Munter included this as one of the variables in the decisionmaking because his research showed that in 60% of all accidents, there were no visible tracks. Note that I understand that Munter's method is intended for use in a specific region of the Alps and that in using his method, multiple tracks on a slope may still result in a no-go. also, for me and the education that i've received, considering that a slope has been skied a bunch should not factor too much into my decisionmaking - it'd probably fit into the human factor type of stuff. personally, i want to ski slopes that are less tracked-up.

From what I can tell, munter's method doesn't consider a reduction in risk if a slope was recently tracked-out but has fresh snow on top.

http://www.clubtread.com/articledetail.aspx?ID=40

btw, people's mentioning of freaky incidents, in 2005, i believe, snowbird had a very large natural or remote triggered inbounds avalanche rip at night during a dry period. the slide which uncovered the large mogul field. i took a course out there right after this occurred and most of the instructors were still scratching their heads. those that weren't were shrugging their shoulders and throwing out full moon and unusual snowpack theories.

[Meathelmet]

some pic,cant just find from my archives where it is from...
some vague recollection that it would be from Les Arcs,but..