Alaska ski guide buried in avy despite airbag

From this morning's Chugach National Forest Avalanche Information Center advisory :

AVALANCHE DISCUSSION
Yesterday was quite active in the backcountry. You had to be perceptive to notice the clues unless you happened to spring a loaded slope as several people did.

There were several avalanches yesterday including naturals, snowmachine, and skier triggered events. Some of those were remotely triggered including the one below from 400 feet away on Tincan. Collapsing (whoomphing) was evident if you happened to be breaking trail or ventured off an established trail.

The most significant event was a full burial of a ski guide in the Placer/Skookum region. The guide was working on stability assessment when the slope broke. The victim took a 500 foot ride, deployed an airbag, and was still fully buried 4 feet deep. The contributing factors to a successful outcome were fast action by the rescuers, a path clear of rocks, and the victim deliberately holding his backpack strap and jacket collar to facilitate an air pocket. This avalanche happened on a SW aspect at 3500 feet during mid-day yesterday. The suspected weak layer is buried surface hoar from late March.

Based on the distribution of the known avalanches yesterday (Girdwood to Johnson Pass), I think most of our region above tree line will be dangerous over the next few days. The avalanches happened on all aspects having no discrimination between sun and shade.

The snow structure responsible for our current problems is a number of crusts on the sunny aspects with some buried surface hoar mixed in. Shaded North aspects won’t have the sun crusts but the buried surface hoar is larger and weaker. Take a look at this pit from yesterday and other recent pits and pictures in the photo gallery.

The “mega storm” coming in today will probably keep most folks out of the backcountry. I am worried about what might happen when this storm breaks. The snowpack will need time to adjust to the new load. Expect touchy conditions for at least 48 hours after the storm ends and possibly longer.

Several feet (like 6+ ft) of new snow have fallen in the last 10 days above 2500 ft in south central AK, after nearly dry and mostly sunny conditions for the previous month-plus since mid-February.

The deep burial is surprising given the huge buoyancy of the airbag (assuming it was a standard airbag pack). Maybe he ended up coming to a stop in a terrain trap, and snow piled on top? Has anyone heard of other incidents where people were buried despite deploying an avalanche airbag?

Some Google searching turned up this paper www.backcountryaccess.com/images/documents/WorkSafeBCReport.pdf with some stats:

Documented Avalanche Incidents

The Swiss Federal Institute for Snow and Avalanche Research (“SLF”) has documented avalanche accidents involving an ABS avalanche backpack since 1990. As of September 2008, the SLF has documented 167 avalanche accidents, involving 200 people who were equipped with an ABS avalanche backpack and 41 people who were not.

Out of the 200 people equipped with an ABS avalanche airbag, the airbags were fully inflated in 180 cases. In these 180 cases with inflated airbags:
* 82 people were not buried;
* 64 people were partially buried;
* 17 people were completely buried with the airbag visible on the avalanche surface;
* 3 people were completely buried with the airbag not visible on the avalanche surface;
* for the remaining 14 people, the degree of burial was unknown.

Out of these 180 cases involving fully inflated airbags, 177 people survived the avalanche (approximately 98%) incident and 3 died (see Figure 3). Two of the three people who died were killed during the downfall, and one was caught in a depositional zone and buried by a secondary avalanche.

Of the 41 people who were caught in an avalanche accident without an ABS avalanche airbag:

* 10 people were not buried;
* 11 people were partially buried;
* 20 people were completely buried.

Thirteen of the 41 people without ABS were killed during the avalanche incident (approximately 32%).

So some burials do happen despite an airbag, although it doesn't say how deep the deepest of the 3 very complete burials was.

I have seen stats that show airbags do not prevent burial in 100% of cases - but still very very high burial prevention and I'd rather stack the odds in my favour.

I am waiting on my ABS as I type. Guess I won't really be using it in similar conditions: 6+ feet in 10 days, what can I say...

Btw, I have heard of a bag getting punctured, so a dual design seems better.

Curious if anyone in Marcus' party who got caught had a bag and deployed...

Curious if anyone in Marcus' party who got caught had a bag and deployed...

Nope -- three Avalungs, two kept in during the ride and the third (mine) torn out when my head hit a tree.

Good vibes to you and your friends, Marcus!
Ivo

Amar, do you know of any similar statistics of people buried vs. non buried with no airbag? I'd imagine less than half of those caught in an avalanche get fully buried anyways, it'd be interesting to calculate the actual decrease in chance of being buried with an airbag.