Colorado Backcountry Conditions

If you can't pay attention to this, you are a moron. This is the Friends of CIAC bulletin for 1/12. Become a member so you can support the CIAC.

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SNOWPACK
The WARNING remains in effect for all mountain areas of CO today. The danger
is rated HIGH all mountain areas...EXCEPT..Backcountry around Crested Butte
& all of the San Juans are now rated at EXTREME. Slides are running
historical distance. Avalanche debris is choked with broken trees, The
largest slide path on Highway 550 (Pumphouse) off Sultan Mtn ran taking out
old growth forest & deposited it on Highway 550, our 2 avalanche forecasters
were trapped between slides on Molas Pass last night for a bit. Lizard Head,
Wolf Creek, Red Mtn, Molas & Coal Bank passes in the San Juans are closed
due to avalanche activity. Road into Ophir is closed with avalanches debris.
The town of Silverton is cut off as all highway access is closed. McClure
Pass in the Central mountains is closed for avalanche concerns. Forecaster
there fell asleep with his headlamp on. Backcountry around Crested Butte is
covered in avalanche debris. We are obviously in one of the most charged
avalanche cycles in many years for the southern and central mountains of
Colorado. The far northern mountains of Colorado are also in a dangerous
avalanche cycle. Steamboat snow safety director called & left brief message
last night about a large slide, though no other details.
I don't often like to say this, but I really do not recommend backcountry
travel at this time in the southern, central & most of the northern
mountains. Places we used to think of as safe, may be at the bottom of a
large path that may not have run in centuries.
Even with marginal visibility more than 300 slides have been reported since
the warning went into effect Friday morning. Wolf Creek Pass has reported
more than 117" of snow since December 29, that's almost half of what most
areas in CO see all year.. The 10 & 12 ft snow stakes on Molas & Coal Bank
Passes have disappeared. One more small concern. roof avalanches in the
lower valley communities due to rain on snow. Some large roof slides have
already been reported.
Looks like a good time to hit your local ski area for best bang for the
buck.
New snow: N mtns 2-5" (Copper 5) C mtns: Snowmass & Ashcroft 14", 12"
McClure Pass, Monarch Pass 11", 10" Crested Butte. S mtns 18" Durango Mtn,
15-16" at Telluride, Wolf Creek Pass estimate 12" with wind gusts to 65 mph
(about 66" since Friday night). Wow, what a storm. Toepfer

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The fucking new snow on top of the weak layer is so deep it's going to take forever to consolidate....... :(

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Originally Posted by BlurredElevens

The new snow on top of the weak layer is so deep it's going to take forever to consolidate....... :(

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with all the respect, i don't think you're right. actually i think, you're quite lucky. as far as i know, big snowfalls (and yours is huge) are the best that can happen to snowpack, especially if it has been weak (weakly layered) before. (which i don't know if it has been in your case) this is due to several reasons:

1. the huge amount of snow means a lot of weight and hence high pressure. so sintering (that's at least how we call it in german: it means a sort of melting together or better: joining of particles due to high pressure but not necessarily heat) will go on a lot quicker than if you would just have some inches of the freshies. and it doesn't matter if its windblown or fluffily fallen snow. that of course also counts for the old layers underneath and the interconnection between different layers. so due to high pressure, temperatures won't even have to climb above freezing level in order to let your snowpack consolidate rapidly. which means? - right: faceshots in the near future.. :D

2. once you've got one big layer well consolidated you don't have to worry anymore about possible weak layers underneath. (and consolidated does absolutely not mean sunburned hardpack as i pointed out above) that's simply because the new layer is strong enough to support your weight and it won't rip of, no matter how much you intend to poke it :D. it's just like a sheet of paper, if its thick enough you can't rip it of and hence make it slide even if its friction with a slope underneath is very poor.

so you'll see. you're avalanche risk is going to decrease astonishingly rapidly (do i have to put two lys 2. :confused: ) even if it stays cold. of course some high temperatures would speed things up a little. but who would want to deal with all the bad consequences. and high pressure solely will work too.

of course all that only counts, if you don't have any strong winds going on. that would screw everything up again, and the new layering would have to be considered as a completely new system.

so watch out for the thin layers, they are the real suckers. first they rip of easily, second they get settled way more slowly and/or only under high temps.

btw if you think your situation is screwed, come over to europe. to quote a recent avy report witch stayed the same for approximatly two weaks (as well as i can quote german in english) "you will find the risky spots wherever you've got enough snow to ski"..

enough written, greg

edit: some spelling - not all ;)

sorry for the poor english

Wow Greg, thanks for the well written reply. I love your optimism, and believe me, I hope you're right! :D

Here in Colorado we have a few feet of rotten granular sitting on the ground. That layed around for a while, and the top 2-3 inches of it got sunbaked....that's our bad layer. Then we got all of this new snow, at least 3 to 4 feet in most places. (more in most) That's the weak layer we're worried about here in the northern mtns. of Colorado.

I hope your pressure theory is true, if we could get that one layer to consolidate, I think I'll be in heaven.

I'm not familiar with the idea, but the more I think about it, the more it makes sense. If the bad layer can get above freezing once, the pressure will condense the granular into a liquidized layer so-to-speak, and then it will freeze again forming the bond. This process would only need to occur once to make the snowpack bomber....wow, thanks so much for the insight Greg! Lets hope it happens soon. -Brett

greg - here is to hoping you are right!

edit: holly shit, your second post... stick around, ok?)

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Originally Posted by BlurredElevens

Here in Colorado we have a few feet of rotten granular sitting on the ground. That layed around for a while, and the top 2-3 inches of it got sunbaked....that's our bad layer. Then we got all of this new snow, at least 3 to 4 feet in most places. (more in most) That's the weak layer we're worried about here in the northern mtns. of Colorado.

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well, to be honest, that´s not exactly as much snow as i thought you were having. i guess, in all my enthusiasm for kirkwood, i confused northern colorado with some places in california.:rolleyes:
but it´s still pretty good. it pretty much depends on how wet or more important, heavy the snow is. all the figures, i've got in my mind, count for europe and not for colorado. and here the snow is mostly a lot more dense.if you've got about 50cm (1,5 to 2 ft) of snow covering a weak layer in the alps, it is much less likely to slide. (of course doesn't mean it's bombproof) but the thicker the coverage it gets, the less important are weak layers underneath.

the effect of sintering does of course effect all layers, but i greatly depends on how much crystalls "touch" each other.
http://wa.slf.ch/uploads/pics/Aufbau...umwandlung.jpg
http://wa.slf.ch/uploads/RTEmagicC_becher_01.jpg.jpg
if that's what you mean by granular, then it is probably going to rest all season long. simply because it doesn't have enough "touching" points to sufficiently melt together, no matter how much pressure you put on. (but it won't transform into stable snow due to warm temps either. the insolation by the covering snow is simply way to good. the snow would literally have to be soaked by water in order to be transformed. but then your mountains would rather look like my fridge than something skiable ;) ) but still, if your covering layer is thick enough you don't have to worry about it. (you probably allready remarked, digging pits during an ongoing season, that the granular stays till spring, but isn't anymore referred to in avy reports - it's for exactly that reason)

well, to sum it up, i would say, 3 to 4 ft is not sufficient to rapidly decrease avy risk. but it is for sure better than if it were just 1 or 2 ft.
it is especially not sufficient if it was windy. in regions where the new snow fell with wind, coverage changes along with terrain. so one can't count on steady layering and will encounter thin layers. and that's were you've got to watch out.
http://wa.slf.ch/uploads/RTEmagicC_s...tellen.jpg.jpg
(^once in the middle of a bowl you're a lot safer than entering it - when the slope redresses, that's where it's dangerous - due to thin layers caused by wind (and i'm at this point not talking about the brittle properties of windaccumulated snowlayers, brittle even when it feels smooth)

I'm sorry that, it doesn't look as promissing as i thought in the beginning. i simply shouldn't be posting in a thread about the quality of local snowpack, when it's about 8000 miles away. :rolleyes: but maybe it was still sort of entertaining, even if you knew already most of the stuff.


@ blurred: i wouldn't dare to simply post "my theory" in an avy thread, without explicitly stating it. it's not my theory, i didn't figure all this stuff out, i'm just quoting. ;)

@ marshal: that's about all i know, there isn't much left to come.. :D

...now, back to the topic (hopefully)

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Originally Posted by greg

it is especially not sufficient if it was windy.

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good thing there are only 50+ mph winds.

I have a couple things to reiterate based on the fact that CO has a Continental snow pack, not a maritime snow pack. The deep slab instabilities (ie depth hoar) which plague CO will likely persist throughout the season. The amount of snow that CO has received in the past couple weeks will likely encourage the faceted crystals at the ground to begin to round, but as greg stated, there simply arent enough contact points between grains for bonding to be very effective. Even if the new snow is well consolidated avalanche activity will continue unless a lot more snow falls. A skier’s weight is said to be able to affect the snow pack up to 1.5 meters (in a continental pack). This figure obviously varies based on the density of the snow. So, until CO has more than 1.5 meters resting on the faceted layer, I wouldn’t count on trusting the snow in avy terrain. Even if there is a lot of well consolidated snow, you must also be aware of areas that may not have as much snow, due to wind scouring, rocks, cliffs, tree wells, etc which will be weaker.

The comment that you are safer once you reach the middle of a bowl than you are on the wind loaded starting zones is true, but it is possible to trigger a sympathetic slide from below the starting zone. If you are at the base of a slide path, and cause a collapse (feel/hear a whoomp) it has the potential to reverberate up the slope and trigger an avalanche above you. I believe this problem is much more prevalent in a continental snow pack than a maritime snow pack.

Just another opinion of CO's snowpack from afar. Well, not really that far, but I don't know the specifics of what is going on locally in CO, so feel free to ignore this post if you dont think it pertains to the current snowpack.

Holy shit, was that a well-conceived post. Thanks!

thanks a lot for clarifying my post and adapting it to colorado conditions. i feel a lot more comfortable now.

rethinking my post, you're absolutely right with what you said about the danger of triggering avalanches from distance in continental climat compared to maritime conditions. because it greatly depends on the density of snow (not actually the bondage) and thus its capabilty to support an unstable slab above. and as you pointed out by comparing the figures (50cm to 1.5m) density obviously differs a lot under average conditions.

(i just wanted to point out, that by trying to throw a glance at a slope (from above) one has most likely already traversed the hot spots (due to thin layering) without even noticing ore in the worst case, noticing it the harsh way.)

without belittling the quality of your post as a whole, this side note deserves some highliting:

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be aware of areas that may not have as much snow, due to wind scouring, rocks, cliffs, tree wells, etc which will be weaker.

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at least in europe, the effect of trees and/or rocks is probably the most falsly interpreted aspect of avy risks.

thanks, greg

greg, thanks for the info
and welcome to the board

Colorado's mid-continental snowpack is always suspect, we get cold nights warm days, and very dry air conditions. Thus leading to hoar frost as temps
in the snow changes. This snow turns to a sugar consistency. You cannot pack it into a snowball. Then you get big storms, like the ones here in the San Juans. 60 slides reported on 550 near Silverton, the highway closed for 5 or 6 days, cleanup not expected to be done for another week.
I personally watched 3 slides come down in the area on tues, big slides full
of debris.
Once the weight of the new snow reaches critical everything slides naturally.
This is when you need to have an intimate knowledge of the BC slopes your
skiing. You need to know for example that a certain slope will eventually slide on the right side, while on the same open slope next to the left trees never slides. Never ski alone, a number of my friends made this fatal error.
I've personally have had 15 friends and acquaintances die in avalanches over the years, not uncommon if you spend your life in the Mts.
By the way, beacon's and all the BC paraphernalia are usually only for body
recovery.

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Originally Posted by kailas

Never ski alone, a number of my friends made this fatal error.

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Was Archie one of them?

Some old mountaineers say "Never trust a depth hoar." Others say, "Never trust a deaf whore." Either one is good advice.

Heads up – During a tour Saturday at Berthoud, a 30ish cm surface slab was releasing very cleanly and easily in all our N to E test pits. On steeper slopes (estimate 35-40deg), this layer was releasing as soon as the column was isolated (shovel compression score of 0). We turned back from bigger lines because of this concern. I believe the slab was sliding on surface hoar.

I won't bore you with the rest of the analsysis other than to say we saw what the CIAC has been reporting with a very consolidated snowpack (one finger to knive) sitting on top of facets/rotten snow.

SNOWPACK
There have been no avalanches reported since early Monday. Warmth and snowpack settlement have brought an end to slab releases. But we cannot, and should not, forget about the deep-slab instability that still lurks in the N&C mtns and the W San Juans. The warm spell has only partially stabilized the middle snowpack where the slab layer lies, and the interface between the slab and the faceted layer beneath. That faceted layer is most prevalent in the Front Range, Summit-Vail, Aspen, Sawatch, Crested Butte, and W San Juan zones. In many areas it is buried very deeply, but as you know deep slabs can most easily be triggered where the slab is thinnest. At the request of local forecasters and observers, I have dropped the BC danger in some locales.

Steamboat zone … MODERATE all elevations and aspects.

Front Range & Summit/Vail zones … MODERATE above TL on all aspects ... Near TL, MODERATE on NW through E aspects, and LOW on SE through W aspects … Below TL, LOW.

Looking ahead, surface hoar growth has been rampant the last 4 days, especially on northerly aspects, and this layer will be buried by the snowfall of Wednesday and Thursday and will be our next weak layer.

A friendly reminder, keep your heads about you. The tone of the avi center bullets have been as "on edge" the last 48hours as I can remember. Many slopes and aspects have transitioned from "fuckin bomber" to "heads the fuck up" in the last two weeks. Have a safe weekend.

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A big weekend coming up. Plan smart. We all know there are weak layers under
slab in most all mountain areas. This means we should be expecting avalanche
activity. Pick your routes wisely. Many paths that ran earlier this year
have reloaded onto facets. Toepfer

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The main face/avy runout across the street from A-basin slid today. Always TONS of tracks on that face. Watched a group of three up there this morning. First one went and no slide or anything, but there must have been some movement or cracking cause the other two in the group waiting up top bailed over the other side of the ridge....

then riding up the chair we noticed the new slide about an hour later....

whats the name of that face?

Wait, the main face is the profesor? I was up there all day but didn't notice it went. Any skiers caught? I know that the top fractured but didn't slide like two days ago with the first few skiers on it after the cycle. Let me know more details, I am trying to get more info as I type.