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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
basically it is the opposite of the crown. so the very bottom of where the slab broke loose. there is a good picture of one in the red baldy avy tr in the "slide zone". or check the "anatomy of an avalanche" thread.Quote:
Originally Posted by greg
nice sunny high pressure day. we summited Mt. Raymond and chose to do some stability testing on a chute just south of the summit. we dropped a 1 ton cornice that produced aprroximatly a 1' crown x 20' x 15'. it broke on faceted snow with a crust as the bedsurface. below the crust was more faceting. the slab had obvious signs of windloading on it. it may be hard to see but it is pillowy there.
http://www.biglines.com/photos/blpic34934.jpg
the crown:
http://www.biglines.com/photos/blpic34940.jpg
the cornice was cut and uncovered the older cornice still visible in this pic. the one dropped was near 1 ton but did not impact the slope that hard:
http://www.biglines.com/photos/blpic34933.jpg
you can see the hangfire and we didn't mess too much with it but enough to find out from a safe area what the story was.
edit to add that when tested the slab produced a Q1 shear that released when isolating the block. the bedsurface was only 1-2mm thick and had plenty of faceting (fist) above and below. the aspect of the chute fall line was due east and the shady slope that produced the slide was more ENE/NE.
the dynamic properties of snow never cease to amaze me. surfers would kill for a wave like this cornice:
http://www.biglines.com/photos/blpic35230.jpg
trackhead, here you go:
west aspect, ~10,000' and 2 pits. compression tests weren't real effective since the slope wasn't that steep.
1st pit had about a Q1-1.5 in the top 1' breaking on facets. down about another foot there was a 3" pensil hard slab surrounded by facets (fist hard) and a melt/freeze (pensil-knife hard) about a foot thick. really interesting but not of real concern for our trip.
http://www.biglines.com/photos/blpic35234.jpg
the slab with the saw in it is a good bedsurface and the weak layer above (facets) is of concern with any sort of new heavy snow or loading. we'll have to see what rb has to say about the new snow and possible winds coming. just remember that the provo mountains have a little more active weak layers currently than we do around here.
http://www.biglines.com/photos/blpic35233.jpg
huge facets. this depth hoar was found about 3' down in the 2nd pit. it continued throughout my pit.
http://www.biglines.com/photos/blpic35232.jpg
i dropped a cornice on the east aspect with near nil vis and a few minutes after i stopped trying to see results and skied away i got this nice vis:
http://www.biglines.com/photos/blpic35231.jpg
Thanks APD.
conditions are looking good right now in most places. as i pointed out to a friend who soloed east twin yesterday, glide avys are ready to go again. he did it friday and my response was it should be good but i would not do it saturday or later. that was just a guess but they are unpredictable and out of our control. all we can do is avoid them.
well, here's what happened saturday in broads fork:
http://www.avalanche.org/~uac/Adviso...ads%20glde.JPG next, there are still a few small windslabs were there is loose snow to blow around. either avoid them or make sure they won't pull you off a cliff, into trees or thru the rocks. lastly, this wet slide prime time so work your aspects. get out early and ski the east faces first, south faces next and wet faces last if you're out farming corn. wetslides are the easiest to avoid. if you are sinking in past your ankles then it is time to find another aspect or call it a day.
here's an example of staying out too late on the wrong aspect:
http://www.avalanche.org/~uac/Adviso...et%20slide.JPG on a day as hot and sunny as saturday was, you should not be on a SE aspect at 2:30pm unless you are confident that it was not adequatly heated in the morning.
well the deep freeze is here. things seem solid right now though sastrugi and wind effected terrain is still evident from the weekend 40-80mph winds:
http://www.biglines.com/photos/blpic36313.jpg
broke trail thru about 2' of fresh and transport. spent the afternoon (1:30-4pm) just looking around cardiff pass. coming up pole line i found the east aspects loaded and very sensitive from the upcanyon winds. they were cracking about a foot deep or better. at the pass you could see the north aspects were loaded but the winds had shifted and things began to load on the south aspect. the visibility, which was not good to begin with, became worse. i headed over to the superior ridge from the weather station and remotely triggered a small 4-6" soft slab from the ridge. http://www.biglines.com/photos/blpic36696.jpg
i went a little further and dropped a little fresh 25lb cornice that propogated over to a nearby obviously loaded chute. it did not appear to have broken into any old snow at the deepest part (~1') of the crown. in the pic you can see it wrapped around the next ridge into some cliffs. it may have pulled out more once it reached the chutes apron but vis was horrible and the trasport blowing onto the south aspects was picking up. http://www.biglines.com/photos/blpic36697.jpg
http://www.biglines.com/photos/blpic36698.jpg
anything without a north facing cornice was starting to develop a south facing one. winds didn't seem to get above ~30mph.
to be honest, it was easier going up than going down. steep slopes were needed for downhill travel but i wasn't about to head down cardiff ridge with pillows above me.
any obs from today? Thinking about Cardiff or Patsy Marley tomorrow.
my only observation was that some people don't tip very well.
i worked all day but i wouldn't have been too excited to get out and ski anything steep. winds changed a bit and lots of new snow is on the ground. i'll take a look at the snotells tonight and decide if it's going to be an inbounds day or not for tuesday.
I was out in Rocky point/Patsy Marley area today. We heard and felt settling in a rocky area on a NE aspect. I also made a block/small slab move on an East aspect, it sheared clean about a foot deep on a small rollover, but it wasn't steep enough for it to travel very far. Later, on a Southerly aspect, a small, 6 - 8" deep wind compressed slab pulled out, but again the terrain wasn't steep enough for it to move very far. There was also heavy wind loading on the N through E aspects off the upper ridgeline today.
yeah, i spoke with an exum guide about some of this today. he said that he felt it was sketch now and would be hitting the resorts after this next storm rolls thru. 3' on top of a layer of facets that is already active is going to be nuts. 5 taps from the wrist is all that it is taking on the NNW aspects in silver. doesn't bode well for this new snow staying put.
i am not all that happy about skiing steep slopes right now before the next storm. it can be done in certain places but the resorts are so damn good right now that it isn't even a choice for me.
These photos are from 8100' on a north facing ridgeline. I was just walking the ridge on a little exploration this morning and this guy pulled out, about 4" from my downhill ski. 34-38 degrees, 20" crown and 30' wide. It pulled down to the facets from the last dry spell and there was a little dirt layer indicating the wind from the start of the first storm last week. I'd keep clear of northerly aspects and use caution on ridgelines - like the avie report says today.
looking east along the ridge I was traveling on
http://www.feedthehabit.com/pics/ski...leys_slab3.jpg
looking west - notice parley's canyon down there
http://www.feedthehabit.com/pics/ski...leys_slab4.jpg
It didn't run far - wouldn't bury you but it'd knock you down and perhaps into a tree or two
http://www.feedthehabit.com/pics/ski...ab_debris1.jpg
debris from another angle
http://www.feedthehabit.com/pics/ski...ab_debris2.jpg
slope angle - 34 degrees
http://www.feedthehabit.com/pics/ski...slopemeter.jpg
Be safe out there.
http://www.biglines.com/photos/blpic37151.jpg
i dug a 9.5' deep pit on a north facing 35* slope at 9,500'. shovel shears produced q2's on a couple slight density inversions and a gaupel layer. each were about 1' apart. R4's and 5's on the same weakly bonded layers.
facets 5.5' down:
http://www.biglines.com/photos/blpic37149.jpg
http://www.biglines.com/photos/blpic37150.jpg
5 taps from the shoulder got the facets to fail. i believe this is the same layer that was active just before our large storm cycle. R-7 -- no failure. i had some trouble isolating the back of the block to that depth so that would have been an issue here. i would guess that it would fail as an R6 had i been able to completely isolate it.
the 3" facet layer shown was what i like to call 2 finger hard or just a little harder than both 4F & fist hard. the 5" below it was also faceted but it was 1F hard. and did not fail in the compression test.
a natural that ran sometime during or toward the end of the last storm. i think this was the maybird/hogum ridge but i can't remember. i took a pic and couldn't remember which one it was for sure. this is a north to northeast aspect:
http://www.biglines.com/photos/blpic37152.jpg
edit: it was the maybird/hogum ridge
the warming has played a factor in these two slides:
http://www.biglines.com/photos/blpic37549.jpg
http://www.biglines.com/photos/blpic37550.jpg
they appear to be 1-3' deep on average and were natural slides of a SE aspect helped on their way by the sunny sky. the SE slopes were crossloaded by upcanyon winds during the storm.
there are unstable slopes out there. be careful over the weekend. we are sure to see more slides tomorrow but i hope no one is there for them to pose a threat to.
i guess you could call these trees flagged. we were on a ridge when this pic was taken. a massive slide took out areas that would otherwise never see mcuh action.
http://www.biglines.com/photos/blpic38219.jpg
this tree is flagged to 45' high. the highest branch i observed broken was on a tree further down hill. the branch was 65' high.
http://www.biglines.com/photos/blpic38218.jpg
just a few snowpack obs:
on E,S and W slopes there is atleast a one inch crust formed that is supportable at upper elevations. mid elevations are hit or miss and lower elevation is just heavy, melted and rained on snow. the E aspects at mid elev had a 2" thick crust that was destroyed by faceting with a coupel feet of wet snow beneith. S aspects had a supportable crust with a couple feet of wet below. upper elev N aspects had 4" fresh with a paper thin crust that wasn't noticable while skiing, just in the pit. no wet snow was observed at high elevation on the north slopes. earlier in the day winds blew in the 20-30mph range and out of the NE loading SW slopes in lcc.