Skier caught in Avalanche near Lake Tahoe

[Tricia]

The season has barely begun, with only a couple storms dumping some snow on us and we have the first report of someone being caught in an avalanche
Skier Caught in Avalanche in Lake Tahoe California 11/11/2015
Snip from article.

SnowBrains has learned from skiers who were at the scene of this avalanche that a backcountry skier triggered an avalanche and went for an estimated 50-foot ride on Elephants Back off Carson Pass (hwy 88) near Lake Tahoe, CA yesterday. The skier was traversing when he triggered the avalanche, was never buried by the avalanche, and was able to stay on top of the debris for the entirety of the ride.

 

[Xela]

Wow. Sounds lucky. I wonder if this is because there isn't all that much snow yet. I know it doesn't take much to bury someone, but I don't know the shape of the terrain involved.

 

[Tricia]

Wow. Sounds lucky. I wonder if this is because there isn't all that much snow yet. I know it doesn't take much to bury someone, but I don't know the shape of the terrain involved.

I'm not knowledgeable about the terrain where this skier was, but the snow we got this past week was insanely heavy.
It was the first time I've heard of power outages in Reno due to downed power lines from falling trees and snow load on branches.
I'm sure that kind of snow is not stable in any terrain.
I wonder if @pais alto has any thing to say from his wealth of knowledge.

 

[JayT]

Wow. Sounds lucky. I wonder if this is because there isn't all that much snow yet. I know it doesn't take much to bury someone, but I don't know the shape of the terrain involved.

I was originally planning to head out there this week - or elsewhere around Carson Pass - until reports came in of all that heavy snow on top. Seeing pictures elsewhere, EB got skied by several others earlier that day so hopefully that was a wake-up call to some. There were actually two different slides in that zone...

The face: http://www.sierraavalanchecenter.org/wed-11112015-1130-avalanche-elephants-back-1111

And the hump, 2 hours later: http://www.sierraavalanchecenter.org/wed-11112015-1330-avalanche-elephants-back

Small crowns obviously, so this time of year burial isn't a concern so much as hitting shark fins during your ride down.

 

[Monique]

So is the rule of thumb about west coast snow being dangerous for 24-48 hours after it falls, and then pretty much safe, just bollocks?

 

[SBrown]

So is the rule of thumb about west coast snow being dangerous for 24-48 hours after it falls, and then pretty much safe, just bollocks?

Overall, compared to here, no. But it's weather. It's always a little bit different, and there are never any guarantees.

 

[Willy]

Actually not the first avalanche I heard of this season. This was posted 7 days ago from Bozeman. Oddly enough, it was two hunters that got caught, neither was seriously injured:

http://billingsgazette.com/news/sta...cle_77c729f6-9c09-5a40-b427-a8d9f2558c56.html

BOZEMAN — Two men who triggered an avalanche while hunting north of Bozeman escaped serious injury despite being carried 400 feet over rocks.

The Gallatin National Forest Avalanche Center reported the men were walking near the saddle of Sacajawea Peak in the Bridger Range at about 9,000 feet of elevation when they triggered a 40- to 50-foot wide slide about 20 feet above them just before 7 a.m. Tuesday.

The men were carried 400 feet down the mountain over rocks, and one man was knocked unconscious. Neither was buried.

They were able to get out of the area on their own. Emergency room doctors cleared them of any critical injuries.

The center did not identify the men.

 

[Willy]

So is the rule of thumb about west coast snow being dangerous for 24-48 hours after it falls, and then pretty much safe, just bollocks?

The first 48 hours are typically the most sensitive. However, very often there will be a buried layer that can persist throughout the winter. We have early season rain over snow cycles that develop a crust that is shear sensitive with snow building over the top for several weeks. At some point, a triggering event can cause a shear that slabs off with often times very large slides. That's why digging pits and doing research on specific areas can be so important. Once deep slabs develop, a warming event can cause instability or any of a number of other factors. The bottom line is don't ever fully trust the snow pack and assume that it's stable, just because it hasn't snowed in a few days. There may be underlying instabilities that are unknown without trained researching of conditions.

 

[JayT]

So is the rule of thumb about west coast snow being dangerous for 24-48 hours after it falls, and then pretty much safe, just bollocks?

It's very often safer after 24-48 hours, but not safe. And if it warms up quite a bit after a heavier layer on top it may actually become less safe. I think a good rule of thumb when it comes to any snow pack is to not have any rules of thumbs. ;-)

 

[markojp]

So is the rule of thumb about west coast snow being dangerous for 24-48 hours after it falls, and then pretty much safe, just bollocks?

Depends on the aspect as well. South facing maritime snowpacks can become unstable because of sun exposure. Continental snowpacks are almost the opposite with sun helping general stability over time and north facing slopes staying cold and preserving/creating long term weak layers. We also don't know what sort of terrain anchors slopes have unless we see them without snow. In the end there are a lot of variables that make 'pretty much safe' difficult to apply universally.