Cornice whompin an essential tool of the trade? or essentially a trade of tools?

[theshredder]

In more continental areas snow can obviously also stick if it gets warm enough, which is why around here steep ice faces traditionally come in season in late spring/early summer, when you tend to have warm storms with a high snow line.

Couldn't that also be because the snow had the entire winter to cool the ground it's sitting on? i.e. there'd be less melt of the snow that is in contact with the ground by spring time because the ground temperature (surface, and at depth) would be a lot lower by then, which might be effectively a lot like reducing snowpack temp gradients.

well yes, that is more or less what crocus and afaik also snowpack were set up for. my basik crocus version runs on a simple text file input with a bunch of meteorological parameters (hourly values), which you can either measure or pull from a model. You can specify an initial snowpack or start with bare ground. I haven't seen SNOWPACK in a long time but as far as I remember it does more or less the same thing. There are operational versions that have a kind of interface where you can input measured meteorological data as the season progresses. Both crocus and snowpack are stratigraphic, 1D models, although at least for SNOWPACK some sort of spatial coverage versions also exist (used e.g. for modelling permafrost areas). You could of course simply loop the 1D model for all the gridpoints where you have appropriate model data, but I'm not sure if you would gain much insight from that in terms of snowpack development beyond what you would figure out without the model.

I'd be interested in using the model for an entire grid of meteorological values as the season progresses. The idea is to provide some kind of real time map, which could reduce the need for observations. You are right though, it may not provide very useful data, at least not initially. All weather models (even the high resolution ones) use a kind of 'smoothed' terrain as part of their lower boundary condition, which creates a mismatch between model elevations and real world elevations). I guess you could also use a statistical downscaling technique as well though...

If you want I can let you know once I get it running and play with your input.

Unfortunately I haven't got a full season worth of hourly data but I'd like to look into a snowpack model. You essentially just turn your snowpack model into a subroutine and call it form the main atmosphere model and you've got a nice tool to look at the snowpack where there are no observations. You could even make it a 2-way coupling and improve the output of the atmosphere model, although that probably wouldn't be worth it for the computational resources required.

[klar]

Couldn't that also be because the snow had the entire winter to cool the ground it's sitting on? i.e. there'd be less melt of the snow that is in contact with the ground by spring time because the ground temperature (surface, and at depth) would be a lot lower by then, which might be effectively a lot like reducing snowpack temp gradients.

A lot of things are possible but I continue to remain doubtful in this case. How would the snow "cool" the ground? I was talking about ice faces, which are already rather cold, but in any case, snow isolates the ground and prevents it from cooling as much as it would if it were bare. I also still don't understand what exactly you mean when you say "melt". You keep mentioning temperature gradients, which suggests you mean facetting/depth hoar, rather than actual melt. (Spring snow packs start melting at the top, not the ground. Melt water may travel down to the ground in spring , causing glide cracks and subsequent slides. Glidecracks also occur when the ground is very wet and warm at the first snowfall, but this does not seem to be what you are describing and has little to do with temperature gradients through the snowpack.)

I'd be interested in using the model for an entire grid of meteorological values as the season progresses. The idea is to provide some kind of real time map, which could reduce the need for observations. You are right though, it may not provide very useful data, at least not initially. All weather models (even the high resolution ones) use a kind of 'smoothed' terrain as part of their lower boundary condition, which creates a mismatch between model elevations and real world elevations). I guess you could also use a statistical downscaling technique as well though...

Unfortunately I haven't got a full season worth of hourly data but I'd like to look into a snowpack model. You essentially just turn your snowpack model into a subroutine and call it form the main atmosphere model and you've got a nice tool to look at the snowpack where there are no observations. You could even make it a 2-way coupling and improve the output of the atmosphere model, although that probably wouldn't be worth it for the computational resources required.

I very much doubt that this would ever be good enough to replace observations. You could probably manage the radiation components reasonably well if you have a high resolution digital elevation model and do some downscaling but all things wind related would be extremely difficult. IMO you would need a full boundary layer model between the snow and the atmosphere model.

Most research does not use the super detailed snowpack models to couple with other stuff but people have been doing things like what you describe, e.g.:
http://www.the-cryosphere-discuss.ne...2191-2013.html
Soil temperature modeling also often uses some sort of snow model.


I believe we have completey derailed this thread.

[spook]

maybe the reason it seems sort of stupid to a stupid is that virtually every time i see it on gopro the people doing it sound and act like assholes.

[Trace Hardslab]

This tool kicks cornices. Not everywhere and not all the time though.

I get the objections to it: thin snow = weak snow. So, continually triggering slides on a given slope can keep it thin/faceted & weak, as opposed to waiting for the snowpack to strengthen over time.

It does make for a heck of a stability test and if you do it enough you'll get to see some really cool shit. One of the best ways to learn about something is to see it. Nothing like seeing avalanches from up close, as long as you don't get in their way!

I hear stories of people who have been riding the "backcountry" for several seasons and the first slide they see is the one they get caught in! This is unbelievable to me. So yeah, kick those cornices, cut that convex rollover & thrash around on test slopes. Carefully!

Make sure the coast is clear. Really CLEAR. Eventually one will run full track & you will be standing there thinking "Fuck, what have I done?!!". It goes without mentioning you can get spanked doing this sort of thing.

Also, if you are in cell-covered area, it is a good Idea to have Sheriff Dispatch or Ski Patrol's # handy so you can call in a "stand down". You don't want anyone getting into a helicopter on your account....

[whipski]

I sure seen a lot of patrollers using it in closed zones. Then ski it after it runs.

[Hey Diddle Diddle]

I am not sure if this incident is an argument for or against cornice kicking.

http://www.tetonat.com/2012/01/24/ta...ain-avalanche/

[Hey Diddle Diddle]

Here is the uncensored link to the Mark White West Monitor cornice kicking in foul-mouthed audio splendor.

http://www.youtube.com/watch?v=Y1WYcQf7yyM

[thebirdhunter]

Hey SFB, just found a use for the 10# weight I never get to use.
Look out below MoFo's!!!!!

http://www.youtube.com/watch?v=q-ilttmWzkw

[Hey Diddle Diddle]

The snow on West Monitor was killed today by ignorant cornice whompers who had no intention of skiing it. The cornice may have eventually fallen naturally and it may have been the same result or maybe not. West Monitor is back to an early season snow pack. There is a lot of moisture in our recent snow. Some cold temps will lock things up and greatly strengthen our snowpack. Please leave the cornices be, on the big slopes we share, when you have no intent to ski it.

[F#*k you cat]

funny that Mark White made the observation and submitted it to UAC.

what is with his love affair with West Monitor cornices.


gotta love that old video of MSB and her clean mouth. shhh no cussin I'm videoing. cracks me up every time

[happytimefunbox]

funny that Mark White made the observation and submitted it to UAC.

what is with his love affair with West Monitor cornices.


gotta love that old video of MSB and her clean mouth. shhh no cussin I'm videoing. cracks me up every time

I do not know this mark white fellow and I do appreciate his obs on uac but some body really needs to tell him stop bringing down the monitors, I'd really like to ski it one day.

http://utahavalanchecenter.org/avalanches/20348

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[happytimefunbox]

Here is the uncensored link to the Mark White West Monitor cornice kicking in foul-mouthed audio splendor.

http://www.youtube.com/watch?v=Y1WYcQf7yyM

There was a whole lot of excitement in that viddy. Boarderline orgasmic? The things people do for kicks...

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[Canada1]

There was a whole lot of excitement in that viddy. Boarderline orgasmic? The things people do for kicks...

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Anyone spoken to him about the thought process?

[totaliboard]

knocked off a human-sized chunk of cornice on a ridge today. the pocket it landed on broke, but only slid about 10 ft.. deeep up there.

its kind of like a snow pit.. certainly not required to ride safely, but it can give you bullseye information regarding stability..

[icelanticskier]

I do not know this mark white fellow and I do appreciate his obs on uac but some body really needs to tell him stop bringing down the monitors, I'd really like to ski it one day.

http://utahavalanchecenter.org/avalanches/20348

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monitors? yer not missing much. short shots fer sure.

rog

[skifishbum]

There was a whole lot of excitement in that viddy. Boarderline orgasmic? The things people do for kicks...

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not quite as retarded as the fat ass goblin tippin lds bsoa dorks but close

Anyone spoken to him about the thought process?

i think ol spindrifty wants to be part of the crew

i gots the cuntinator on ignorze i bet it was cuntworthy ego fluffin roj
it's what he does
well hopefully the i know it will go but how big yahoos can control themselves and show some restrain till shit bridges

[icelanticskier]

^^^^^^fucking thinned skinned gaper that SFB is. Still. Oh the lulz.

rog

[simplypow]

I read a DOA publication from the 70's that demonstrated the measurable, but seemingly negligible impacts of cornice killing on spring watershed. I'm assuming there are still reasons for blasting cornices to prevent sublimation, but letting the snow pile up is gives one perspective. Triggering the slide and skiing what's left along the margins (hangfire) is selfish, but depending on how things ran it could give you a better idea for what's stable on a particular slope, as well as valuable obs that could be extrapolated more broadly. But just because it didn't go doesn't mean it won't, so I guess it's better to use the cornices as huck points, and just put your money where your mouth is.

[happytimefunbox]

I don't think anyone disputes stomping cornices is a tool to assess slope stability, its a damn good one. But the use of it to get yer jollies is the issue. In particular the monitors on the park shitty ridgeline, n facing, generally always loaded ready to pop. You can look at the and tell yep uber windloaded, lets not go there. Bringing them down when you have no intention of skiing them seems kind of senseless to me. This white fellow puts up obs on Uac almost daily, tours with Kobernick and posts shared obs with him. He has to know the score. Hasn't he posted in the wasatch obs thread in the past? Maybe he could come on here and esplain why he can't walk the PC ridge without stomping the cornice on west monitor....

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[skifishbum]

i don't think spindrifties stomped the last one he was just wanderin by out touring with his ego
he rolls that way
and i think the pottymouth self appointed queen o wasatch tried to justify it somewhere in a thread here
search or gear up and get your soli thurs on
we can go out to wolvie and go pro ourselves creating repeaters
like the pros

[wra]

I found these today.



Coulda, shouda, wouda stomped on um but...no gopro.
I guess nature will just have to run it's course.

[My Pet Powder Goat]

Today We witnessed a natural cornice break on conehead PC ridgeline. It started causing some sluff, untill about half way down a piece of bouncing cornice released a pocket to the ground probably 70-80ft across up to 2-5ft deep.

Mark White was nowhere to be found

[icelanticskier]

You guys ever consider that white may be saving someone's life by clearing the monitors? Lots of folks move about along those ridges and many of them that don't know how dangerous those slopes can be could easily be lured in.

rog

[Gepeto]

I was taught by a wise kootenay inhabitant that you can chop over any type of terrain trap anytime.
Other than that, don't f with it unless you've deemed what's below skiable now and you intend to make
turns on it now or you already have an objective and this is your pre-sighting look for a subsequent lap.

Otherwise preserve

[icelanticskier]

I was taught by a wise kootenay inhabitant that you can chop over any type of terrain trap anytime.
Other than that, don't f with it unless you've deemed what's below skiable now and you intend to make
turns on it now or you already have an objective and this is your pre-sighting look for a subsequent lap.

Otherwise preserve

Sometimes ya just don't know what lurks below. So do ya feel lucky? I agree with the preservation statement.

rog