Building the Colorado snowpack

[smitchell333]

next page success this time.


Was out today - Loveland area. Wind blasted. South facing stuff above treeline was pretty well cleaned down to the crust from 2-3 weeks ago. Made for pretty low danger skiing, but aint powder.

Varying slabs and powder below treeline and on Northly aspects. Inverted in a bad way in spots with rotten snow low down and stiff slab on top.

With a big storm or two esp with any warm spell we might start talking about "bridging" over the hoar.

[FrankZappa]

Wolf Creek backcountry was full on conditions all day Sunday 12/17. By mid afternoon natural releases were happening on many aspects. It made for an exciting but spooky trip. Snow seemed to be somewhat wet in the AM then turned colder in afternoon. All was below timberline.

Bigger slabs seen were on southerly aspects in gully/terrain traps deposition zones consisting of the fresh. Crown was from maybe 3-4" up to 12"-15", 100 feet wide and running to gully bottom (50-75 ft). Enough to make debris plenty deep in the bottom trap.

On northern and eastern aspects much sluffing seen. Suspect mostly running on fridays reported hoar frost layer. Did not witness any stepping down, but had seen report of another hoar frost layer buried deeper - so as load increases with this storm expect potential for that.


A few word on group dynamics.
I usually travel with just my one partner, especially on days when the danger is up like that. Yesterday the group was at 5. Group dynamics really go to hell easily I decided. It was way too easy to get sucked into a bad spot by the actions of another member of the group. And traveling with new people isn't as easy as with your usual partner. It really take a lot of verbal communications between all, unlike an almost telepathic type deal that can come from years of experience with ones regular partner.

Many factors played into the mix, even after a plan was decided on, it easily changed shortly thereafter when a portion of the conditions changed. - at 3:30 with not much more than an hour of daylight left as weather was deteroriating even more, we fortunatly came across a skin track back up. One member took the bull by the horns and just flat out put his foot down and said that was our out. It was the right call as desending conditions were getting much worse - less snow depth and increasing down fall mixed with being constantly sucked toward the gulch bottom, exposures and a long slog out. So a climb back up and over the top, late in the day, with some allready tired people was the answer. Over a thousand or twelve hundred vertical up and then a ski back to the highway brought us back to the car right at dark.

More lessons learned. You learn them almost every trip out. - I will be more cautious about whom I tour with in regards to conditions in the future. I think I'll go with the more extreme the conditions the smaller and tighter the group.

[Below Zero]

^^^thanks for the info FZ^^^

I thought about the group dynamic when you mentioned that you were heading out in a group of 6-7 people. It seemed like a lot. I'm glad you shared your story here. Thanks.

[Pow4Brains]

Dunno if this is localized, but I took this pic today and it almost looks like there is a little dust layer in there. Be careful out there folks!

[Pow4Brains]

From CAIC today. May be related?

Snowpack Discussion

Strong winds formed pillowed, hard wind slabs on slopes that face NE-E-S, while westerly faces and ridges have been stripped clean. Observers indicated that the snowpack yesterday was surprisingly solid. There were, however, clean shovel shears lower in the snowpack on an old dirty wind/sun crust.

[Phatstix]

I thought surface hoar was a function of cold, dry night air drawing the moisture up out of the snow as well as a dry sunny day that generates vapor in the subsurface snowpack.

For SH to form there must be water vapor in the air and a TG above the snow surface. Little to no wind is key because too much turbulence changes the TG.
i.e. Cold front moves out on a cloudy day and a clear, windless night follows.
BTW - thanks for the weather links!

[pechelman]

^^ if i remember it right

the air temp must be warmer than the surface temp and the dew point higher than the surface but lower than the air. and the surface needs to be below freezing. this is in addition to calm air, and if what I remember is right, around 3mph is the ideal condition for SH growth.

[Phatstix]

^^ if i remember it right

the air temp must be warmer than the surface temp and the dew point higher than the surface but lower than the air. and the surface needs to be below freezing. this is in addition to calm air, and if what I remember is right, around 3mph is the ideal condition for SH growth.

I tiny bit of wind like 3 mph could actually help development by renewing the vapor. Too much kills it.

So, it appears in Colorado we are damned by the wind and at times damned without it.

[Phatstix]

Observation:

I was skiing two days ago on Richmond Ridge in Aspen. A couple guys a few days before came down the skiers left of McFarlanes Bowl (A line). Given it's a bowl, when they neared the skin trail towards the bottom of the line they naturally were brought towards the middle. It appeared that a burried SH layer was sitting below the new 6 inches or so of new. It zippered 200-300 yards uphill and cracked the top 50 yards wide. No stepping observed.

I say this because it wasn't steep where it initiated and sometimes it's difficult to comprehend what a bad layer can do to whats above you while traveling in 'mellow' terrain.

[Shredhead]

I say this because it wasn't steep where it initiated and sometimes it's difficult to comprehend what a bad layer can do to whats above you while traveling in 'mellow' terrain.

It's going to be scary back there when we finally get some new snow. Sorry I missed you this trip, be back in a couple.

Be safe!

[~mikey b]

natural on South Ptarmigan yesterday - lots of wind last night, with more expected today and tonight - I wonder what we'll see out in the world today.........

[Rontele]

natural on South Ptarmigan yesterday - lots of wind last night, with more expected today and tonight - I wonder what we'll see out in the world today.........

Mike, we are lucky to have you and your knowledgable avy background on board in CO in contributing to this thread!

[smitchell333]

Big Winds all day today and winds 100MPH on the continental divide forecast for tonight on the front range.

I imagine we'll see some big slides next few days - if there's any snow left.

[~mikey b]

Mike, we are lucky to have you and your knowledgable avy background on board in CO in contributing to this thread!

Thanks. I hope I can live up to that, Rontele. I'm no expert, but I'll try to share what I see out there. I'm very new to this snowpack, so I have a hell of a lot to learn.

What I learned today: the snowpack has a lot of energy right now. We were out at Boss Basin, and saw cracks extending far from the propagation point, above skiers by about 30', and also heard and felt a bit of whumphing. We manged to kick off a small slab with a ski cut pretty easily.

Instability tests: ST-E, Q2 & CT15, ~30cm down - ST-M, Q2 & CT30, ~ 60cm down.

Those were in line with the natural we saw yesterday on South Ptarmigan that failed about 30cm down, and the skier triggered slide just down the ridge from that one that looked like it failed on the old snow, too.

CAIC has raised the hazard forcast to high this afternoon.

Oh, yeah, I almost forgot - I met Dean Cummings up on Ptarmigan today while he was out with Vail Powder Cats. Nice guy.

[Rontele]

Big Winds all day today and winds 100MPH on the continental divide forecast for tonight on the front range.

I imagine we'll see some big slides next few days - if there's any snow left.

Nah. it has all sublimated or is in Kansas now.

[FrankZappa]

Central Colo's finally getting some dumps over the last couple weeks. I hadn't ventured up into the high country since just bfore X-mas, trying to avoid the holiday crowds. And it has snowed in the lower elevations too which it seemed it hadn't hardly done yet this year. I actually think BC stuff can be done at ALL elevations here in the Arkansas valley - which is a rareity, especially mid winter instead of the more common waiting 'til spring heavy upslope storms.

Friday's storm dumped near 20 inches at Monarch, and around a foot or so through the valley, on top of the 1 - 2 feet left from the previous couple of storms in the preceeding couple weeks. Light density, Colo's finest... Until the dreaded wind cranked up Fri nite / Sat. At first light on Sat. mornin' all the collegiate peaks actually looked skiable... for about an hour, then all those feet of new was stripped bare to be deposited in some other far away place.

My plans for skiing were just as quickly blown away and instead turned to hours of shoveling and plowing in the 30 - 50 mph est. ground blizzard that lasted all day. By Sun. I was able to make it out and headed to Monarch pass for a quick BC tour first followed by an afternoon in the leftovers within the ski area.

I found quite a few cars at my usual pullout and figured it would be well tracked and beat by the wind effect. When I asked a passing lone snowboarder who was headed out about the conditions he told me that most was kind of thick but that Gracies was great. I skinned up a perfect skin track (usually it's beat by foot traffic here) and caught up to a gal that was solo also at the top of another lil' peak. She was good and avy savvy and had said that initially she was trying to catch the two guys ahead of us 'til she noticed they had no BC gear with them - she quickly bailed and headed the opposite direction from the saddle, but was glad to hook up with me for a run.

Anyways... I'm thinkin' about all the folks out there and the sketchy stuff they do. That guy that rode Gracies for instance. (and I'm sure there had been plenty of others too - I watch 'em all the time on that obvious avy face). There's been hardly any snow 'round here up 'til a couple weeks ago so the TG is out-a-hand for El-o base, HUDGE dumpage and then HUDGERER wind loading onto it... we all heard about the big Berthod slide on Stanley and this is much smaller but similar in aspect and prevelent loading, and of course... consequence.

Well guess what I find on today's CAIC Sawatch range report:

Snowpack Discussion
A human triggered slide occurred on Monarch Pass yesterday in the Gracies slide path. It is a lightly treed east facing slope. The soft slab was 3-5 feet deep, 60 feet wide and ran 100-150 feet on an old layer of facets at the bottom of the snowpack. The slide was triggered by the third skier near a convex shaped rock outcrop. In other locations, observers found reactive new windslabs that were easy to trigger.

New snow, combined with strong winds, has formed slabs on a variety of aspects. Winds have been gusting in the 50's and 60's from the west and southwest, forming slabs on N-E aspects above and below tree line. These slabs are sitting on weak faceted snow. Watch for side loading of smaller terrain features and gullies. Avalanches that initiate in the new snow could trigger slides that break into deeper weak layers. Use caution and conservative decision-making if venturing into the backcountry. If you are in or near terrain steep enough to slide, only expose one person to the danger at a time and have an escape route planned.

Soooo... maybe that gal had the right idea when we see or run into folks out there that don't have the gear, or the smarts to stay clear of certain slopes at certain times - that is, just turn the other way and get as far away from them as possible.

[lemon boy]

Anyways... I'm thinkin' about all the folks out there and the sketchy stuff they do. That guy that rode Gracies for instance. (and I'm sure there had been plenty of others too - I watch 'em all the time on that obvious avy face). There's been hardly any snow 'round here up 'til a couple weeks ago so the TG is out-a-hand for El-o base, HUDGE dumpage and then HUDGERER wind loading onto it... we all heard about the big Berthod slide on Stanley and this is much smaller but similar in aspect and prevelent loading, and of course... consequence.

thanks for the report FZ!

It's interesting to bump avy accidents against the obvious clues method it is silly how easy it is to get to 3 and a 4 or a 5 doesn't come that long after either.

[FrankZappa]

thanks for the report FZ!

It's interesting to bump avy accidents against the obvious clues method it is silly how easy it is to get to 3 and a 4 or a 5 doesn't come that long after either.

You're welcome.

Care to elaborate more on the "obvious clues method" and it's associated scale?

[lemon boy]

Lee's Avalaulator thread goes into it a bit although I wasn't able to find anything online dealing with the full paper so this is just typed out of TAR:

The clues:
Rating: considerable or higher
Avalanches: reported or observed in the last 48hrs
Unstable Snow: colapsing/cracking deep trailbreaking etc..
Path: obvious path, recognizable by a novice
Loading: new snow, wind or rain last 48hrs
Trap: terrain traps
Thaw: melting of the surface and accompanied by sinking into the snow as high as bootops (skis on)

The numbers:
(clues then % of avy accidents)

2 or less, 2%
3 or less, 8%
4 or less, 23%
5 or less, 53%
6 or less, 90%
7 or less, 100%

Per McCammon, at 3 he starts feeling uncomfortable at at 4 is where the myriad of group factors start kicking in bad.

It appeals a lot to my very 80/20 outlook.

The Dec issue of TAR had a lot of great stuff: Obvious clues, ECT and strategery digging.

[iskibc]

Well, our pack has officially gone to crap as of 1/8/07. I was optimistic up until the past few days, but today really sealed it. Got up to about 12K in the IPW this afternoon and found some of the nastiest and most variable snow in a long time. Lot's of windboard, but also lot's of pillow formation around starting zones and places you really don't want that type of formation. Lot's of variability, even below treeline. It's ok now, but will be tough to figure out after the next storm. Lot's of varying surfaces on this wind drifted snow. Nothing that will stick well with just about any snow, so no matter where you are, it will be sketchy.

Just a good time to keep you avy eyes open and play it safe.

[Phatstix]

I agree Iski. The Elks are pretty much in the same boat. The wind did a number here too.

Avalanche Activity: Yesterday avalanches were reported on a variety of aspects. A natural avalanche was observed at the top of Highlands Ridge at 12,000ft on a SE aspect near the Thumb. This soft slab avalanche (SS-N-R3-D2-I) was big enough to kill a person and ran roughly 2,000ft, occurring at the interface of the storm snow and the old snow. Two natural slides were observed at 11,000ft on a cross loaded W aspect near Ashcroft. These two slides (SS-N-R~-D2-I) ran 1,000 vertical feet also occurring at the storm snow old snow interface. A fourth avalanche was reported on an ENE aspect at 12,500ft in the West Willow drainage with a crown of up to 3ft deep. These slides are in addition to multiple avalanches observed on Saturday. Saturday’s slides all ran on NE-E aspects involving just the storm snow. Two occurred on Richmond ridge around 11,000ft, with the others running between 12,000ft and 13,000ft in the Castle Creek drainage.

Imagine if and when these step?

[MOHSHSIHd]

I haven't read any of this thread yet (but soon will).

Anyway, I was asked to share my thoughts on observing other tracks and therefor assuming that an area is safe to ski (this in relation to what happened to me and my roommate today).


Our observation of other's tracks definitely swayed us to ski an area that I know is usually unsafe and it could have cost us our lives. It was definitely a combination of huck-fever and blatant disregard of my avy knowledge that lead to our decision to ski what we did (east facing aspect, slid with 14" crown, 60' wide and 120'+ long.)

Don't really know what else to say except that we were just plain stupid today......no other way to put it.

[smitchell333]

Well, our pack has officially gone to crap as of 1/8/07...Just a good time to keep you avy eyes open and play it safe.

Agreed for the time being its kinda fucked up...

Out on a PM tour today I found mostly severely inverted with wildly varying from fluff on top of depth hoar to hardslab on top of depth hoar below/at treeline. Above treeline it was mostly scoured down to the old crust. I think at/right at treeline or steep windloaded above Treeline are the most dangerous right now although i'd really never trust anything inverted which is almost anywhere not really deep.

Saw some scary slides that had run last few days right above treeline where smaller slides triggered DEEP hardslab - spooky stuff.

Good news, I think, is there is sufficient depth that once a warm/freeze cycle of real signifcance hits it should settle/bridge pretty well and we'll be back in business for bigger lines. And with more snow predicted the short term danger will rise to high and then gradually subside.

Last year it aint, but praise the Lord it also aint 2002/2003.

[Phatstix]

I haven't read any of this thread yet (but soon will).

Anyway, I was asked to share my thoughts on observing other tracks and therefor assuming that an area is safe to ski (this in relation to what happened to me and my roommate today).


Our observation of other's tracks definitely swayed us to ski an area that I know is usually unsafe and it could have cost us our lives. It was definitely a combination of huck-fever and blatant disregard of my avy knowledge that lead to our decision to ski what we did (east facing aspect, slid with 14" crown, 60' wide and 120'+ long.)

Don't really know what else to say except that we were just plain stupid today......no other way to put it.

Phish, that's super cool of you to admit that. There is nothing that can happen but positive things from sharing with us. We've all either done the same thing or wanted to! I would really like to hear more about the situation. And most importantly, glad you are here to tell us about it.

Go to the thread I just posted and follow the directions for the shear test and compression test. You may find that backcountry skiing is way more fun when you actually take the time do look at the snow, observe the wind patterns, make predictions, etc. I do anyway. I think it adds the enjoyment that ski areas don't really provide and I feel like I'm really IN the mountains.

10-4? Over-

edit: after re-reading your post, I hope I didn't sound like I was telling you something you already know. Thanks again for stepping up and sharing.

[~mikey b]

Minturn was in the clouds when we left this morning, but Vail Pass was bluebird. Managed to get in a couple runs off Ptarmigan and it was goood.