You could move pretty fast, and climb pretty amazing pitches, do have videoQuote:
Originally Posted by TahoeJ
Link
https://vimeo.com/195392361
https://vimeo.com/195392361
You could move pretty fast, and climb pretty amazing pitches, do have videoQuote:
Originally Posted by TahoeJ
Link
https://vimeo.com/195392361
https://vimeo.com/195392361
Relying on bridging isn't a winning "long term strategy" if you're in the wrong terrain (Google "Sheep Creek avalanche accident." But also you're not exactly bike riding around in starting zones, etc. I think the bigger concern is if it doesn't warm up before another round of precip we could have some isolated areas with rotten snow that are fine now, but won't be fine once you add the weight of new snow on top. Lots of uncertainty and high consequences in these areas, even if probability of triggering is micro.Quote:
Originally Posted by TahoeBC
No, because many (most?) people don't know that Moderate also means that large to historic scale avalanches are possible in isolated areas via human trigger. The NA Danger Scale provides no specific information about scale, consequences, or location. Some people who don't understand the ratings stay home during Considerable danger days with Windslab problems (don't ski lee faces above treeline) and then go ski gnarly terrain on Moderate days with Persistent Slab problems (don't ski anything near runout zones where persistent slabs may exist). I'm guilty of such things.Quote:
Originally Posted by TahoeJ
The scale won't shift to low unless "human triggered unlikely" applies. This won't likely happen until PST results become much less consistent for propogation potential in pit data provided by professional observers and the public observations as well. I can't remember the last time we had a persistent slab problem rated Low, but I'm getting older with less functioning brain cells these days.
Schralph, there's only so much you can dumb stuff down (and this applies to much more than just avy forecasts). The person that doesn't take the extra time to read the actual forecast beyond the rating is most likely out there without training, without digging pits, but they got the gear and the fancy new airbag, so they're good to go. Reading the fine print would just confuse them anyway, because then they would need to figure out the difference between lee and windward, know how to determine different aspects - too much work, not enough gnar.
And there's been plenty of times with a low rating and PWL, especially when spacial variability makes them harder to detect, but it's known that they exist somewhere within the area with potential for big consequences.
And TahoeBC, killing it, unreal pics. How often does the front tire punch through unexpectedly throwing you OTB?
Not once today, but it happens, all depends on conditions, doubt you could possibly hit better conditions than what we had today, pretty rare especially for this time of year until you get a good freeze thaw cycle going in the spring.Quote:
Originally Posted by mmmm...pow!
Looked like a cornice break triggered it and then it stepped down several times. This pic from the SAC report shows it pretty well I thinkQuote:
Originally Posted by Ottime
Hard to tell here but there was a shit stain running down the main chute that is just a hair left of center in this pic
Attachment 194984
this shows it I think
Attachment 194986
and the steps down
Attachment 194987
I hear you, and I don't think we should dumb it down any more. I think presenting the hazard on such a simple scale encourages that simple mindset. In other high consequence activities, your first time showing up to a local break or crag and having no clue what you are doing, you get put in place pretty quick if you throw up an American Death Triangle anchor, etc. We should be doing the same on the track.Quote:
Originally Posted by mmmm...pow!
I just get so tired of hearing "no signs of instability!," and "bomber!" from people out on the skin track who don't know the problem and just center punched some stupid exposed line with known persistent slab problems.
I don't think I've seen "historic" used in the size scale before from SAC. Slides at that magnitude are what created things like the bowls on trimmer peak, I'm guessing.
Last years PWL slide cycle got some people pretty good, unfortunately, even a local pro with a guided group.
It ain't about penetration....
Those bike look like fun!
Its possible I would have been on the lift with my bud that's on a snowboardQuote:
Originally Posted by jcolingham
Not sure what they mean by historic, unless they are talking about potential in the future. I'm thinking historic happens with a deep base, can't see there being enough volume in a 40" or whatever we got now base to produce something so monumental. But yeah, while there's been some deaths in the area in recent years, it's been a while since buildings or stands of trees have been taken out.Quote:
Originally Posted by bodywhomper
Given the nature of that scale and our propensity to define the 100-yr, recurrence event, that's my guess; "Historic" is the 100-yr event, which could mean pulling down bigger trees.
With the additional weight, it'll be interesting to see what happens and how the warnings are elevated. If it starts hitting the fan, I bet NWS issues a warning.
TahoeBC, regarding your penetration observation, here's part of the little lecture on the SAC forecast, "These kind of avalanches will be harder to trigger in areas where a thick and supportable rain crust exists, but they may be possible in those areas as well."
That bike stuff looked fucking fun!
Your wife might disagreeQuote:
Originally Posted by bodywhomper
Point taken, have not done any digging yet, might dig a pit tomorrow to see whats going on if I get out, just looked at the video above, it is pretty eye opening.
Yeah what was that, a PST of like 8/100 with a super stout slab on top? That is a real deal Colorado snowpack. Last time we had something even close to that nasty it rained all the way into the facets and rounded. Not sure we'll get so lucky this time. Hopefully we find out sooner rather than later!Quote:
Originally Posted by TahoeBC
i was trying to set you up for that.... :DQuote:
Originally Posted by TahoeBC
Just saw this video over at the Snow Brains FB page. Chris Davenport giving a great visual of todays conditions at Squaw.
Wow!
https://www.facebook.com/snowbrains/...7718115573334/
Just to add a little perspective on all of this historic avalanche talk. I saw big slides at Rose on the slide side that I have never seen in my 13 seasons out here, so I'm inclined to be extra cautious for a while.
The only activity I've ever seen is right under the lift just lookers left of Hollywood rock go a bit and that's it (slide side isn't very steep)...that actually didn't seem to go. What went was the entire zone a little below that from the lift to the skiers right side of gold run and it ran all the way to the 'mine train' cat track. It pretty much ripped to the ground. Also the entire 'climax bowl' lookers left of the lift went pretty good. Here's a visual pink = slide
Heavenly's webcam page is killing it...
Attachment 195016
We might have ~40" of depth, but we got 10" of liquid in there. That's a lot of mass, which times 'a' means of lot F!Quote:
Originally Posted by mmmm...pow!
Under such conditions, it is plausible to expect that the D scale (which measures destructiveness in mass) for a given slide might push historic boundaries while the R scale (volume-based) may not. Of course if the runout conditions are favorable for a long path length slide (as Davenport demonstrates with the low elevation ice layer?), the R value could get cranked up as well.
A nice write up on this here:
http://www.avalanche.org/moonstone/F...ne.TAR29.3.pdf
So considering how much rain we got over the past week - and if that didn't make it through that thick slab down to the bottom PWL - are we pretty much stuck with this layer until it just rips all of the 30+ degree faces clean over time as more weight is added? Or is there still a realistic chance for it to consolidate? If not, you'd expect the resort patrols to just bomb it all clean and start fresh... unless they're just waiting for it to go naturally and save them the trouble and explosives.
There's other ways for it to fix itself. New rain higher than the last rain. New snow buries the trigger points, etc.
^ Should see rounding setup if we get more snow, right? Unless it gets unusually cold, a good meter of consolidated snowpack should be enough to keep that temp gradient below 10*C/m, and we're not too far from that.
Has anyone been out to know how skiable Echo Lake is lately?
Could you explain a bit on the trigger points getting buried? I thought this was a faucet layer sitting right above the dirt in most of the northern facing bowls above 8k that had snow remaining from the storms in october? These slabs will break simply by load I assume?Quote:
Originally Posted by powdork
Well I believe the issue is that this layer sits directly above the dirt, so the embodied energy of the ground itself is keeping it warmer.Quote:
Originally Posted by stanmarsh
No expert here or actual avy education here, but just food for thought....
Hm this new snow on crust is going to be great...
From the SAC public observations "A piece of the crust sawed out of the snowpack at around 8600 ft on an E aspect."
http://www.sierraavalanchecenter.org...212_120816.jpg
I think PD means that it's harder to realistically penetrate down to trigger points if the weak layer gets buried deeper into the pack. But that alone doesn't make the underlying structure any safer, it just means that more force is needed to load it to failure.
Only time and weather will indicate if and when north faces can come back into play. Lots of SWE will test it ... whether to failure or eventual rounding. Anyways, it's snowing again, plenty of good south facing terrain to ski, assuming the new stuff sticks to the crust :)
From what I've read, the more snow (especially warm storms in maritime climates) the better for healing depth hoar (facets). Mostly to reduce temperature gradient and the thicker snow pack make it much harder to trigger.Quote:
Originally Posted by stanmarsh
"More than most other weak layers, the strength of depth hoar varies quite dramatically from one location to another, depending mostly on the depth of the snowpack. Remember: thin snowpack means a weak snowpack. Thicker snowpacks insulate the cold air from the warm ground, have a small temperature gradient and thus a stronger snowpack."
I have a feeling this layer won't even be talked out on SAC in a week or so.
I got out Sunday for the first time but avoided due north terrain specifically for this reason. The E and E/NE faces were skiing great. There's plenty of safe skiing to be had. Just stay off steeper/rockier N facing shit for a bit (or dig to the bottom first) to let the snow do it's thing.
I'm bored. Watching in rain..........
Some footage from last year.......BC, West Shore, Mammoth Area and North Lake.
https://vimeo.com/192407030
Went and checked it out today, very skiable with "Water Skis"Quote:
Originally Posted by bobz
Attachment 195056
Wow - doesn't even look icy below the N facing slopes. Thanks for the pic.
Here is another one looking towards Becker
Attachment 195059
You won't see the ice without sun. If it's below 9k it became ice. Don't snow in the trees fool you either. That's ice too.Quote:
Originally Posted by B__
As per further up, yeah, I wasn't sure about that layer with more snow and cold with the proximity to the ground and whether that would make any difference.
I hope it doesn't last - and I've read Tremper and Snow Sense (a few years back and need to revisit) - but may have chosen a good year to finally get my AIARE 1 next month with Alpenglow. Jan 13-15 if anyone else here is doing the same, as some were saying several weeks back.
Regardless, never a bad thing to discuss this stuff publicly.
SICK!!!Quote:
Originally Posted by dhklauer
Indeed. Although I haven't contributed, I've been following along closely the last few pages and have gained some great insight on the current conditions. Keep on discussing guys, I'll keep lurking :smile:Quote:
Originally Posted by TahoeJ
Whoa, I knew it was warm up there, but had no idea it was that bad. Thanks. And quite a lack of coverage on the south-facing side, too. Guess it's either Carson or Rose areas this weekend.Quote:
Originally Posted by TahoeBC
I remember several Tahoe seasons in the last 20 years during which we had problematic layer in the early season that disappeared (from the avalanche equation) when rain soaked the whole snow pack. Skiing sucked during the rain event and you had to be cautious for the next several days but after that the snowpack was completely different from before the rain event. I am hoping that happens again.
i hope this is what happens.Quote:
Originally Posted by BGnight
the persistent weak layer problem last January was different than the current problem. for those that forgot, last january's problem was buried surface hoar and the avi cycle lasted jan 5 through jan 19.
Latest forecast by nws for the reno area does not mention snow levels even once. It does sayTo me, this means it will be an all rain event below 9k again. I hope I'm wrong.Quote:
The most notable change in the evolution of this major
weather event is that the arrival of the cold air push appears to
be delayed a few hours, with the bulk of the cold air coming after
4 AM early Friday morning across the I-80 and US-50 corridors.
edit- the sacramento office has a better forecast
Quote:
Snow levels will initially start above 7000 feet today, but fall
rapidly as the front passes through. By early Friday, snow levels
could drop down to 2000-4000 feet, but heavier precipitation will
be winding down. There is still some uncertainty with how snow
accumulation the mid-slopes of the northern Sierra will get, but
the pass levels will see at least a foot and likely more.
Nice edit! Whats the couloir around 3:00?Quote:
Originally Posted by dhklauer
Pinner Couloir near convict lake.Quote:
Originally Posted by Wobby
can't say i've seen a seven foot wave on tahoe. who's surfing today?Quote:
LAKE TAHOE: DANGEROUS LIFE THREATENING BOATING CONDITIONS ARE EXPECTED WITH WAVE HEIGHTS 3 TO 7 FEET.