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here's the place for your daily observations from the backcountry, inbounds or even your backyard (trackhead) if applicable. even if you haven't been up and just have some thoughts to share about what the winds or sun will do to the snowpack. post it up here so we can all benefit.
hopefully there will be some pics as well.
http://www.biglines.com/photos/blpic31674.jpg
Don't build your house in a slide path. Or atleast don't let your kids play behind it on a high danger day. Or.............ski cut it frequently, or track it out frequently to help stability.
Because one day................it will slide.
http://fritzrips.com/v-web/gallery/a...icture_012.jpg
We (snowbasin) had graupel fall on top of the 3% density snow from the other day. The snow would easily fracture under the wieght of a skier but there was no obvious bed for it to run on. Soft slabby.
sometimes graupel can be its own bedsurface. be careful when trolling out there.
i noticed plenty of wet activity today at the lower elevations in lcc. after a 4hr wait for the canyon to open i got 4 trams at the bird before they closed. on the drive down starting at maybird gulch i noticed that the chutes/couloirs on the north aspects had some wet debris in the runouts. most all the paths had it but the most noteworthy were the y and the y-not. they had some good stuff in the bottom. it probably started only about 1,000' vert up or 7,200'. hopefully the rain will solid things up after we get this next cold storm. things should bond well this round. with a freeze those lower elevations should consolidate just fine. i don't know about the south aspects and how the crust will react to the rain but it should be interesting. anybody have anymore info?
edit: oh yeah, i forgot to mention that there is plenty of graupel to go around out there.
Not in the BC, but related. At Jackson Hole 2 days ago, we got about 24" of snow up till noon. From noon to 1pm, the wind went from about 20 knots up to 40 to 50 knots with gusts in the low 60s. The 24" of blower pow turned to a slabby wind packed slab... and I triggered two small [dr evil] mini-slabs [/dr evil] each about 10 feet wide and running for maybe 30' off lower sublette ridge. The snow showed all the classic wind slab signs, fracturing between the skis while traversing and breaking apart. After that run all lifts were closed (which just meant closing the gondy) due to avy danger - it seems that headwall had been windloaded and they were afraid of it sliding and crushing all the gapers getting of the gondy who would be completely oblivious. Not that anybody who knew more could do anything about it...
edit: I'm stupid. This isn't in the Wasatch...
http://www.biglines.com/photos/blpic32358.jpg
there are still deeper instabilities out there that can be skier triggered if one hits a sweet spot. these will settle soon if they aren't messed with. most of the drainages in bcc/lcc look like war zones right now. the skiing is highly variable most places and we have not been getting a deep freeze at night. remember that if it does freeze to check the snow below. it may not have frozen overnight whereas the top 2" did. so look for the south 180 to produce point release at your feet and larger wet activity starting earlier in the day than expected. after a few good melt freeze days we should be back on track. until then, watch your slope angles and check how far you're sinking in. if it's past the ankle it's time to split. loud pow can be found at mid elevation north aspects. take some time to survey the damage nature and wpg has given us. it is quite humbling.
in spring our creeks will look like the uinta's.
this one shows lots of missing foliage. the damage goes about another 30 yards behind me and knocked down another 10 fully mature pines. talk about powerful.
http://www.biglines.com/photos/blpic32374.jpg
the pow is stacking up on the mid elevation sheltereds. south aspects felt a little sensitive off the ridges yesterday due to the loading. the strong winds will allow loading a little further down than usual. should be near a foot of transport over there at the upper elevations.
http://www.biglines.com/photos/blpic33039.jpg
o baby! :eek: bring some this way!
i borrowed this post from t-tips because i felt it was informative and relavant over here. i hope you don't mind, WRA.
Quote:
Originally Posted by WRA
found all sorts of interesting things about today. the winds were in the singles to teens with gusts in the low 20's. they came predominantly from the sw and west but also switched to out of the nw for a brief time today. we saw one natural occur on a ne aspect that was only 6" deep and didn't run too far. the sw aspects seemed to be particularly sensitive to a skiers weight but were only breaking down to the crust layer 2-6" deep. south aspects in general had trouble bonding to the 1.5" crust that formed last thursday night.
here are some pics:
small slab on a north aspect that started by a natural cornice fall 100 yrds away.
http://www.biglines.com/photos/blpic34411.jpg
it sympathetically released this slope just under cardiff pass:
http://www.biglines.com/photos/blpic34412.jpg
some of the fresh cornices were particularly sensitive:
http://www.biglines.com/photos/blpic34415.jpg
the south slopes were not bonded well at all, especially the sw aspect. these released stored energy but did not go in most spots. the ones that did were minor and did not run very far.
http://www.biglines.com/photos/blpic34413.jpg
http://www.biglines.com/photos/blpic34414.jpg
most of this should settle overnight if the snow stops. if not, you might want to give it a day.
12345678Quote:
In theory, the slabs within yesterday’s new snow should settle out fairly quickly and they will be much harder to trigger today because the new snow was so wet and dense, and it was clear overnight. What I’m more worried about is all the water weight added over the past several days continues to overload the weak layers of faceted snow, now buried about four feet deep. I would not be surprised if some eager beaver triggered a deeper, more dangerous avalanche today. These deeper avalanches will be more difficult to trigger but they will be very large and hard to survive. So today, like yesterday, is a good day to avoid slopes steeper than about 35 degrees, especially slopes with recent deposits of wind drifted snow and slopes that face north through east. Since the new snow is dense and supportable, you can have plenty of fun on gentler slopes today. Finally, you need to watch out for wet sluffs and slabs on steep sun exposed slopes when the sun makes the snow surface wet and soggy.
well the snow seems to be settling out for now. the january facet layer did not seem to be reactive on todays tour. there was talk of larger slides in hogum and white pine that may have slid on those facets but other than that the slides were confined to the new snow, which is good.
we saw evidence of windslab failure on the north aspect where patsy/wolverine meet grizzly gulch. the slab was small and only ran a short distance while entraining loose snow. probably started by a cornice kick(s). http://www.biglines.com/photos/blpic34677.jpg
this is a slide path that ran earlier in december and once again recently.
it appears to have run during the last storm and has had some new snow deposited on top of it already. you can see the stress fractures in pic #2 and the short running debris in pic #3. notice the skin track. unless you are sure of the conditions you do not want to put your uptrack here.
http://www.tetongravity.com/usergall...2-05%20001.jpg
http://www.tetongravity.com/usergall...2-05%20003.jpg
http://www.tetongravity.com/usergall...l_100_1952.jpg
once up to honeycomb we checked out a line that we skied earlier in the year. gramps was here not too long ago, before the last round of storms and noticed a 4' crown in this chute. now it has been filled back in with new snow and wind transport. you can see that it was possibly having a hard time holding its bond with the smooth bedsurface left over from the last slide. the evidence is this crack cause by the creep in the upper layers of the snowpack. creep occurs when the new snow is settling at a faster rate than the snow benieth it. as the snow packs down it also moves downhill. the old snow is still going thru this process but at a much slower rate.
http://www.biglines.com/photos/blpic34674.jpg
as we headed for silver fork, we found a huge cornice that has vexed gramps for some time now. after two attemps to cut it, it still vexes him.
http://www.biglines.com/photos/blpic34678.jpg
on the north aspects the loud pow was out in full force. the surface hoar appeard to be more advanced and larger on the northeast slopes and smaller on the north west. both pics are from the NE aspects.
http://www.biglines.com/photos/blpic34675.jpg
http://www.biglines.com/photos/blpic34676.jpg
Thanks for the observations APD. I saw that same slide up on Patsy Marley yesterday. We tried to kick and cut some cornices down further up the ridge, but didn't have much luck.
APD,
Interesting you talk of the crack in the new wind deposited snow on the old crown. The same thing is ALREADY happening again behind my house. The big 3-4 ft. crown is completely blown in and rounded over in places. And from the road, you can see a crack that runs all the way across it.
Damn avalanche production machine, some hills are.
yeah, i figured you'd have that slope be a repeater after a slide that big. watch out when it gets really loaded again. if i lived there i'd be doing pits weekly up by the flank and in the new snow. how slick was the bed surface? it doesn't look like all the debris left the track so you may have that going for you.Quote:
Originally Posted by Trackhead
Well done, apd. Good to see those visual trouble signs noted. Ranks right up there with seeing it firsthand. Well, not really, but your reports are enlightening.
there are still windloaded pockets of instability out there. yesterday we had 2 skier triggered avalanches that were nasty. today was no different.
more evidence of skier triggered avalanches:
http://www.biglines.com/photos/blpic34832.jpg
http://www.biglines.com/photos/blpic34835.jpg
with the daytime heating the cornices were easy to release. slabs with sensitive weak layers will be no different:
http://www.biglines.com/photos/blpic34812.jpg
be on the lookout for evidence of windloading and avoid it:
http://www.biglines.com/photos/blpic34833.jpg
look for naturals or other recent activity and dig pits to see if the instabilities have settled out yet:
http://www.biglines.com/photos/blpic34834.jpg
as usual call the avy forcast center before going out. 801-364-1581 is the regular # that is updated around 7am. make sure and check the early report (801-364-1591) which often contains more detailed info that is important to travelers.
How'd the skier do in what appears to be a ride over the rocks in that first shot?
broken clavicle. he actually started much higher on another, smaller slab. here's a link to another thread.Quote:
Originally Posted by splat
apd - what you are doing is really incredible. i`ld love to have someone like you over here telling me each day what to look out for AND explaining why.
well here I come with a question about this slide:
http://www.avalanche.org/~uac/Adviso.../Superior1.jpg
I find it a really strange place for a fracture line. (I know it has been triggered by previous slide, but still) could somebody explain that to me. does it have to do with some altitude related weak layers?
I would have expected it to slide either a little bit further down (just befor the rollover) or a lot higher - but right in the middle? (suggestions anyone - not just apd? ;) )
Quote:
Originally Posted by greg
well as you can see in the pic there are a few rocks that can make for a shollower point in the snowpack and more likely release point. i can guess that is likely crossloaded from just above where the suicide/homicide saddle is. the sometimes erratic upcanyon winds can both top load and crossload over there. that being said, i haven't seen a crown there before but i doubt it is the first time it has happened. it may not have slid above because of sloughing on the steeps that prevented slab formation but at the bottom it tends to mellow and become thinner. this likely broke on facets which grow better in a thin snowpack. so there could have been the same slab both top and bottom but the weak layer was weaker on the bottom because of the thinner snowpack. the white dragon is a strange beast that no one has completely understood yet.
does this make some sense? i'm having a hard time wrapping my brain around this one also.
yeah, that does make a whole lot of sense. i did get the parts of the fracture zone on lookers left as well as on lookers right. but i couldn´t figure the part in the middle. as it is a compression zone, i would have expected the upper slopes to slide too. but continuous sluff gradually stabilizing the snowpack on this steeper slope throughout the season seems to me a very good explanation. hadn´t thought about that.
the zigzag line on lookers left, sort of "shortcutting" one weak spot with the next rock is quite interesting...
well sort of. you have to remember that just below that compressive zone is a cliff band thus making it a hanging snowfield with little to no compressive properties. it is hard to say since the stauchwall is completely gone.Quote:
Originally Posted by greg
Quote:
Originally Posted by greg
yeah, it seemes to have propogated from rock to rock (thin areas) all the way across.
thus your sluff theory would even make more sence..Quote:
Originally Posted by AltaPowderDaze
"stauchwall"? don´t know english.. :( and it´s neither part of my dictionary.
better to see in your pic. :)Quote:
yeah, it seemes to have propogated from rock to rock (thin areas) all the way across.
http://www.biglines.com/photos/blpic34832.jpg