Elyse Saugstad, a graduate of Dimond High in Anchorage, not only further describes her experience on her website, but says that in April 2012, Chugach Powder Guides will be hosting an Epic Athlete Experience with her at Girdwood. It will include heli-skiing.
So what is an avalanche airbag system? First, here's a photo of a system when it is deployed:
Skiers can wear the ABS on their backs either deployed or undeployed. However, most skiers will wear it undeployed, because once the pressurized capsule in the activation handle is released, the activation handle and cartridge must be returned to a dealer for replacement. Deploying the system is simple and virtually instantaneous; before the ride, the skier simply screws the pull lever into the left strap, connecting it to a nitrogen canister inside. In case of emergency, the skier can pull the lever, which will inflate the pack into a full-sized body buoy (illustration HERE). Survival rate of ABS users caught in avalanches is said to be 90 percent, although the ABS cannot protect one against trauma from running into trees or rocks.
A company called ABS provides a graphical illustration comparing the ride of an unequipped skier with an equipped skier:
The ABS has 10 different components. On the Engadget website, Gary posts a comment providing a more in-depth technical explanation of how the ABS works, but uses plain English:
Immediately upon triggering and becoming involved an avalanche the wearer pulls a rip cord, bags inflate. This increases the wearers buoyancy in the moving snow hopefully preventing burial when the snow stops. If the wearer is buried then the bags will slowly deflate, this accomplishes two things; prevents the mechanical suffocation of the wearer due to being encased in snow(avalanche debris sets up like concrete within moments of stopping due to the heat generated by friction during the slide) and will have a breathable air pocket.
These devices typically use a venturi vacuum inflation device where high pressure gas forced through a narrowing opening increases in velocity, on the other side of the narrowing there is a low pressure zone. Positioning holes at the low pressure zone causes surrounding air to be sucked in and then forced through a check valve into the bags. Using this method, bags inflate but do not pressurize, users will not be crushed by the bag deploying in a confined space and the volume of the air canister for the system can be reduced.
As mentioned by others, these bags do not prevent trauma which is a high percentage of avalanche fatalities.
You can also read a list of FAQs provided by ABS.
Cost of Unit: North Face says the total cost of their ABS Patrol 24 Pack and ABS Vest, which is slated to be launched by fall 2012 in specialty stores, will be around $1,050. This includes $900 for the basic unit and $150 for the nitrogen tank. TeamCCWasilla has information on how Alaskans can get one of these units. Whether this is a good purchase depends upon where and how often one is exposed to the threat of avalanches. Someone who goes skiing in back country on a regular basis ought to consider it; but the ABS website indicates that some dealers may rent these units on a one-time basis.
But as Alaska Dispatch's resident curmudgeon Craig Medred reminds us, beacons and ABS backpacks are no substitute for common sense. They're merely last-ditch survival and recover tools.