Avalanche Safety Packs
Although they have been around in various forms for quite a while, in recent years the number of Airbag Avalanche Safety Packs available on the market and the number seen on the hill has increased drastically.
There have been constant improvements to the safety, functionality and weight of these packs season on season and the modern offerings give added peace of mind while reducing the sacrifices of weight, practicality and pack design in some of the earlier generations.
All Airbag systems have one or two large fabric sacks which inflate when triggered. The basic principle involves keeping the skier near the surface of the flowing snowpack which lessens the chance he or she will be suffocated or crushed and increases the chance that they will end up on or near the surface. The principle (Inverse Segregation) is the same as that which keeps brazil nuts near the top of a bowl of mixed nuts—bigger and less dense objects tend to rise to the surface. “Avalanche air bags are not flotation devices,” says Pascal Haegeli, an avalanche safety researcher at Avisualanche Consulting and an adjunct professor at Simon Fraser University’s School of Resource and Environmental Management in British Columbia. “They don’t work like a life vest that you use when boating. It’s not a buoyancy effect, it’s a sorting effect. The bladders make the skier a larger particle within the avalanche debris.” (Scientific American)
Various numbers are commonly bounced around as to the survival rates of people involved in avalanches with and without Airbag Safety Packs, with figures of up to a 97% survival rate commonly used. As ever with statistics they require careful interpretation. This blog form Bruce Tremper from the Utah avalanche centre makes for interesting reading which puts some of the claims into perspective but could be considered as underplaying the effectiveness of these Systems. The quote below is taken from studies done by ABS when reviewing their system in real life avalanches which we feel puts things into perspective quite well.
"The bottom line is that in the 262 activations that occurred during the ABS
testing cycle, 3% died, 97% were visible on the surface, and 84% were
uninjured and able to self rescue.
In the SAME AVALANCHES, 67 folks were involved that were not wearing ABS
packs. 25% of those folks died (so 75% survival) and only 57% of
those folks were visible on the surface."
Which ever way you interpret the data from the studies done on avalanche survival rates, it remains that the chance of survival in increased and likelihood of injury or deep burial decreased if you are wearing and manage to deploy an Airbag system.
This video from snowpulse has some basic info on their system and sobering shots of avalanches.
Please note: There is no substitution for carefull judgement and planning, including awareness of current snow conditions, terrain and weather patterns and how they will affect the avalanche risk. These safety systems are not intended to turn the wearer into and invincible superman or woman. Airbag Packs and Avalungs etc are there as a last resort. Whatever safety equipment you carry, The best way to survive an avalanche is to not be in one.
What to consider when buying an Airbag Avalanche Pack.
Important things to consider are:
- The style of the Airbag (size, shape etc)
- Do you need to replace cylinders or is the system refilable and how easy is it to do?
- Can you fly on a plane with it?
- Capacity, comfort and features of the Rucksack
There are 3 main system currently on the market (Mammut/Snowpulse, ABS and BCA) here we'll look at the advantages and disadvantages of these system.
Mammut use the snowpulse system. There are two types the Rescue Airbag System (R.A.S.) and the Protection Airbag System.
The Mammut/Snowpulse R.A.S. System
The Mammut/Snowpulse Protection Airbag System.
As you can see from the images above the R.A.S. system inflates behind the head and neck which whilst keeping you up in the avalanche doesn't give much protection to your head and chest and will tend to tip you face down in the flow.
The Protection Airbag System inflates around the head, neck and chest which offers increased protection against injury as well as keeping you floating face up in the flow.