Huge Avalanche in CB Backcountry

F

=FLO=

Active member
Feb 9th - White Mountain, Skier Triggered but no one was buried, 1 mile wide, 10 foot crown

avalancheuo3.jpg
 
could you imagine being caught in that..... the guy who triggered it is lucky as shit, obviousy he had some mad karma going his way
 
ya how the fuck do you survive breaking a 10 ft crown?? i hope he just skiied it out like it was all part of the plan.
 
White Mountain, WSW at 12,000

observation226photo.JPG
White Mountain, SW, 12,400, 14:30

HS-ASr-R5-D4-O/G

6 Skiers/No burials

Six backcountry skiers were involved in the avalanche on White Mountain on 02/09/08. The skiers were making their way back to the Snodgrass TH from Gothic via White Mountain. Prior to leaving the Hut, they had assessed snow stability as Good below treeline and Poor at and above treeline, and had called the avalanche hotline to get the CBAC's forecast which called for considerable hazard on all aspects and elevations. On the ascent up to pt. 11498 they were no signs of instabilities. Continuing above treeline on a SW aspect the snow was supportable and began to warm up. At 11,700, there was a shooting

crack in a small crossloaded pocket on a SW slope around 36 degrees.

The crack proagated for 20 feet and nothing moved. Continuing up the ridge there were no other signs of instabilities but there were many naturals on various aspects and lots of evidence of windloading.

The group decided to ski a low-angle (25 degrees) rib that split two large SW facing bowls on the northern ridge of White Mountain. The snow on the rib was stiff and supportive but as they made their way down the rib it appeared there was a much deeper windslab than anticipated. They skied one at a time from safe zone to safe zone. At 11,650 the slope angle increased to 30 degrees and the snow changed from supportable windslap to punchy (ski pen ~50cm) soft snow. The fourth skier remote triggered the slide as he was skiing 3 feet left

of the left most track. The crown broke 50 feet uphill of him and propagated up to the top of the southern bowl. The southern bowl ripped down and presumably undercut the northern bowl which slid second. The remaining two skiers skied down to regroup and the six skiers skied down the debris and out to the East River Valley.

Crown depths varied from 5-10 feet. The slide ran 2000 vertical and debris travelled 1 mile from starting zone to its terminus on the flats. Both slides went wall to wall and from map/photo comparisons ran approx. 1500 feet wide in the north bowl and 500 feet wide in the south bowl.

CBAC
 
My opinion may be worthless as I am an eastern flatlander, but if you assess snow stability as poor above treeline, why would you continue above tree line?
 
you dont out ski a slide like that, you just fucking pray you dont get caught in it try your hardest to fucking self arrest before you get going...
 
Yes i too wonder that, so do many people that live here, it was the first warm day in like 3 weeks and it is south facing, pretty careless if you ask me
 
people just think... "it will never happen to me"

That is a uhh rather large slide. Pretty sure i would have shit a brick if i started that, even if i knew it wasnt sliding above me or where i was.
 
When they went aboved treeline and checked to snow and it seemed stable they just assumed that it was ok. I could not even imagine setting off that slide. It scares me but at the same time makes me want to get into backcountry skiing and learn all the stuff you need to know to be safe.
 
yeah reading that article, from what they saw it seemed pretty safe, but I don't know why they would continue after they called in and got the avalanche warning
 
i meant that. he survived so he must of stopped himself, THEN he should have skiied it out like it was nothing.
 
what's really interesting (and scary as hell!) about this whole scenario is that the guy who was basically leading the tour is a guy who's around 60 years old and has been one of the leading International Mountain Guides for about 4 decades.... what it comes down to is it can really happen to anyone in any given situation....

the other scary as hell part is that they had the shooting crack run to the ridge on the right side of the picture and that hit the cornice which propagated the whole right bowl, the left bowl which slid, which is 3-4 times bigger than the right, was a sympathetic release to the right bowl - that is fucked!

glad everyone made it out ok, but this is scary shit... our snowpack has been pretty bomber all season, but there are some super deep instabilities now, and the mid pack is incredibly heavy (while still solid), but that weight, particularly on warmer days when the snow is settling is creating a terminal point of weight...

but the skiing inbounds is ridiculous!!

FLO - I skied toilet bowl two days ago and it like a 55-60 degree groomer, no mandatory in or out!!
 
I think they figured since they were on a low angle slope they were ok, but it seemed they failed to realize there was a super steep open bowl loaded with snow above them. the lower area was probably holding the weight of the snow above them and gave out, or something along those lines. That is my guess but god damn would that scare the poop out ofme.
 
I think that ridge was a pretty safe decision regardless. At 30 degrees need have to have pretty unstable conditions for that to be sliding, in which case both those bowls would have already gone and indicated the deep instabilities. Pretty scary shit regardless, we had one that wide up here in MT earlier this year, but I think it was only 4-6' deep---still enough to absolutely destroy anybody in its path.

But yeah, good decision on the guide's part, they took by far the safest-looking route down that.
 
Going out to ski cb for the first time next weekend, my buddies there told me they were gonna scare the shit outta me but dayum, im still so damn excited!
 
My friend saw it happen, I made it to where I could see white mountain about 2 mins after it happened. Warren Miller has been fliming at CB and had a heli on the mountain that day. It went over and circled for a few mins looking for victims. Honestly that picture doesnt do it justice. That is one HUGE mountain...seeing it in person almost makes you question back country skiing. Anyway....pretty gnarly....
 
The Crown or crownline is the point that an avalanche starts from. Its like a crack in the snow and below that line is where the avalanche is, So the bigger the crown the bigger the slide.

And any crown above 3' is big

even a slide with a 6" crown can kill you without too much trouble.

citadeldry_startzone_021703.jpg

 
wow thats big...^ a crown is the part above where the slide broke and is measured in feed down to where the slide ripped out from...
 
Pretty much, so when you see pictures from an avalanche theres kind of a wall of snow at the top where the slide started from, if that wall is 10' high its a 10' crown, and thats fuckin massive
 
I have lived here in Crested Butte for 23 years and this is the biggest slide I have ever seen.  Jean Pavillard was the guide leading this group, and as JesseW put it, he is VERY VERY expierienced.  He has been to the top of Everest. Not that that matters.... But, this goes to show that expierience does not matter.  Kids- check out cbavalanchecenter.org for some more big ass slids that have happened here. It's insane. Flo- thanks for posting this.
 
I'd say it does... just to a certain extent. It will lessen the risk ever so slightly, but by no means reduce the risk by any significant amount
 
no, the crown is just the shelf of snow that is left behind, the snow that doesn't slide. notice it looks like a cornice.

crowns can break however deep, and however wide across.
 
with this being America I suppose the ski patrol take the blame for not making the mountain safe and allowing people to ski the line?

Surely not
 
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