Author Topic: Alps Avalanche story  (Read 2200 times)

Offline triguy

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Alps Avalanche story
« on: March 20, 2015, 02:39:21 PM »
Read this on kzone figured it would be good for discussion here as well....

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Offline Admin Al

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Re: Alps Avalanche story
« Reply #1 on: March 20, 2015, 04:33:21 PM »
Man...that is some scary S%#t...
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Offline NEAlpineStart

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Re: Alps Avalanche story
« Reply #2 on: March 20, 2015, 08:46:45 PM »
We watched this today in an avalanche course and there is some positive self-critique from the victim. Travel techniques, rescue response, human factors... lots to learn about here. Very lucky that the victim got his ski pole above the surface considering those who were near him only had shovels & probes, but no beacons.

Offline lucky luke

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Re: Alps Avalanche story
« Reply #3 on: March 25, 2015, 01:12:59 PM »
Read this on kzone figured it would be good for discussion here as well....

it is good for discussion for sure. heuristic behavior, instead of fact? Here is the text: " I noticed a muffled ‘whumping’ sound as our skis broke through a thin layer of hoare frost about 30cm under the fresh layer of snow. We stopped and discussed our options. Due to this particular gully being known amongst locals as a safer option due to it’s short length and low pitch, also taking into account the fact that we had skied the line on previous trips in similar avalanche conditions without an issue,"

for those who remember what his an heuristic, I think that a decision base on local opinion (that can include avi post) and previous attempt...is not safe. This is short cut to what happen really.

I think that the wump was wind slab. As i can understand, the guy had a good "I buy a course" knowledge on what is hoare frost. Not sure that it is the reason why the wind slab collapse.

Offline NEAlpineStart

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Re: Alps Avalanche story
« Reply #4 on: March 25, 2015, 08:59:06 PM »
...
I think that the wump was wind slab. As i can understand, the guy had a good "I buy a course" knowledge on what is hoare frost. Not sure that it is the reason why the wind slab collapse.

I know I will regret this tomorrow morning.

From victim:

"we were hit with a large snowstorm that dumped close to one metre of snow over a 48 hour period."

The problem here was Storm Slab (or Persistent Slab), not Wind Slab. There are zero indications in both the report and in the video that indicate this was a wind effected area. It was a steep rollover that triggered on a persistent weak layer, below tree line. Where do you come up with a wind slab guess?

Quite obvious while watching the video. In 3 feet of new STORM snow. You might also argue it was a persistent slab if it was on "hoar frost", or more accurately called Buried Surface Hoar.

LL... if you don't know the difference between Storm Slab and Wind Slab perhaps you should pony up and "buy a course". You might actually walk away with some share-able knowledge.

EDIT: And "local knowledge saying this is safer" is quite different from expert advice (avi post) listing the danger as 4/5 on the European scale...
« Last Edit: March 25, 2015, 09:03:29 PM by NEAlpineStart »

Offline NEAlpineStart

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Re: Alps Avalanche story
« Reply #5 on: March 25, 2015, 09:08:45 PM »
...
for those who remember what his an heuristic, I think that a decision base on local opinion...and previous attempt...is not safe. This is short cut...

This comment of yours (edited for brevity and accuracy) is SPOT on though... "Familiarity" is alive & well in these type of accidents.

As far as prevention (and ignoring the broken response to the accident), ignoring the whumping and skiing so close together then over a convex roll = accident, regardless of what an avalanche bulletin might have said...

Offline lucky luke

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Re: Alps Avalanche story
« Reply #6 on: March 30, 2015, 04:31:50 AM »

LL... if you don't know the difference between Storm Slab and Wind Slab perhaps you should pony up and "buy a course". You might actually walk away with some share-able knowledge.

it is true that I don't know all the terms that they used to characterize avalanches. In my point of view, hoar, deep hoar is more interesting for cross word than for mountaineer.

My knowledge is basic: loose snow avalanche versus slab avalanche. Loose snow is mostly on steep avalanche terrain and after a storm. Friction is the key. When the weight of the pack is higher than the friction, there is avalanche. If you know a way to calculate the weight of the pack...you will win the Nobel price of safety avalanche. The snow plus the climber equal a danger for sure during a snow storm, but, as a choice, I will cross a loose snow avalanche at the beginning of the storm, not after two or three days.

Slab avalanche can be trigger when a slab is formed. Here is the characteristic of the wind slab avalanche:" Wind Slabs can be very hard, and may present a hollow drum like sound as you traverse across slope." I think that it is the  "woump"  that the climber heard. I was with one of my friend climbing a route. I was leading and go up hill and around a gully. When we go back, I let my partner gong the first. He didn't avoid the gully. We heard a "woump" and a ten feet wind slab went down where my partner was. We saw the river of snow going down as my partner struggle to stay on his feet. We were safe as it is a good place for me to bring partner to show them avalanches.

What i was saying is that he have a clear indication of a air under a slab, but he decided to follow advice of local and previous attempt instead of logic. he had a crust with air under it. As he went over, the crust broke and the air was release...it is the "woump"

 

Offline NEAlpineStart

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Re: Alps Avalanche story
« Reply #7 on: March 31, 2015, 11:59:45 AM »
...

What i was saying is that he have a clear indication of a air under a slab, but he decided to follow advice of local and previous attempt instead of logic. he had a crust with air under it. As he went over, the crust broke and the air was release...it is the "woump"



Agreed. The type of slab is quite irrelevant given both the rating for the day and the whump that was experienced prior to deciding to huck it over a steep roll-over.

The devil is in the details though. There are differences in what we track when making observations in relation to Wind or Storm Slab, but whumping is bulls-eye info for any avalanche problem. You are definitely right about that and the effect of Human Factors.

I know there is a separate thread on this but it is related so if you bothered to follow LL & me's rant you should spend a minute or two reading this 1st person account of a snow ranger getting caught a couple days ago... it's enlightening:

http://www.mountwashingtonavalanchecenter.org/2015/03/30/march-29-2015-first-person-narrative-of-lip-avalanche/

Offline lucky luke

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Re: Alps Avalanche story
« Reply #8 on: March 31, 2015, 05:53:20 PM »
In the alp avalanche story, it was clear that there decision was made on heuristic familiarity clue instead of logic.

What is logic? I think that one most make the distinction between a mountaineer, a person who ski outbond zone and people in a ski resort. for instance, the mountaineer is going to follow arret and ridge, avoiding slab. Outbound skier, will go directly on slab and avalanche slab in some case. and ski resort will learn hoar ice, wind, and all the way to predict at 100% an avalanche in their area. What is logic: don't learn the technique to be at 100% sure of an avalanche if you want to do mountainering. Don't learn the technique of an outbond skier if you want to do mountaineering. On there ski, they can plan to get out of the dangerous zone before they get catch by the avalanche. It is not possible with ice tool.

In fact, in general, and more precisley in climbing, When you thing that the situation is degenerating...it is because the situation is degenerating. A small slab, as small as the one over a pocket of snow, can be treaterous.