The
streamlined ABS® TwinBags generate unparalleled dynamic lift
during all the phases of the avalanche.
Is the effect of an avalanche airbag based on the same principle
as a life jacket? No! This is a common and dangerous
misconception. Why? Because an avalanche is not a liquid, like
water. It is made of granular material, comprising particles and
chunks of snow of various sizes.
During an avalanche, the material is constantly mixed and unmixed.
You can observe this effect every morning in your breakfast
cereal. Interestingly, the larger ingredients such as nuts and
dried fruit are normally on top. Scientists call this phenomenon
segregation. It is also often referred to as the "Brazil nut
effect". In 2001, scientists at the University of Chicago proved
the following statement: "In granular mixtures or granular
materials, especially large granules will work their way up to the
top, even if their specific weight should, in fact, force them to
the bottom. The developers of the ABS® system have used these
scientific findings and optimized the ABS® system according to the
rules of the "Brazil nut effect".
ABS® does not believe in the life jacket fairy tale and relies
instead on scientific findings and the analyses of hundreds of
avalanche accidents.
Life jackets help you in water. But an avalanche is not a
waterfall and has absolutely nothing to do with calm water. An
inflated airbag will therefore not automatically keep you on the
top of an avalanche. The ratio of additional volume, buoyancy and
the overall shape with your body is decisive.
In the most dangerous phase, when the avalanche comes to a halt,
the rapidly compressing snow forms a solid mass consisting of
lumps of snow, slabs and ice chunks. In this situation, you will
only stay on the top if you are lying flat and are sliding on the
top of the snow. Round or cushion-like head airbags located around
your head only offer little additional lifting surface and do not
place you in a better position when the avalanche comes to a halt,
which means you can still be buried. Your ABS® TwinBags have been
designed to ensure that you are in the most horizontal position
possible when the avalanche hits you and effectively prevent you
from sinking back into the snow.
An avalanche has three phases. The start, the breaking up of the
wind slab, the descent of the snow masses and the halt and
solidification phase. What are the interactions between these
phases and an avalanche victim with an activated avalanche airbag?
During the start phase, it provides the means of immediate escape;
during the descent, the ABS® TwinBag prevents you from sinking
back into the snow, and during the crucial halting phase, it
allows you to slide on the surface of the deposited snow.
Why is a horizontal position so important during the halt phase?
The avalanche, which consists of snow crystals of different
compositions and densities, lumps of snow, slabs and chunks of ice
or rock, takes the form of moving layers, one above the other. The
bottom layer first, then the next higher layer, and so on.
If you throw a large air-filled ball into an avalanche, it will
always remain on the surface, even when the avalanche comes to a
halt. The constant formation of new snow layers results in the
ball being pushed along on the surface. But if you attach an
anchor or human body to this ball, the anchor quickly becomes
entangled in the layers of snow. The ball gets stuck and the
following layers of snow build up and eventually cover it
completely.
So when it comes to avalanche airbags, this means: that everything
protruding below the airbag acts as an anchor and prevents the
avalanche victim from being pushed along on top of the moving snow
mass. A conventional mono-bag, that is only located around the
upper body or head area, acts like a ball to which an anchor, the
human body, is attached. In real life, when the avalanche comes to
a halt, the lower section of the human body is the first part to
be trapped, because it cannot move along with the upper layers of
snow, which eventually bury the victim.
In contrast, the two ABS® TwinBags attached along the sides of
your body allow for a horizontal position. The risk of getting
stuck in the solidifying layers of snow and being buried by the
following avalanche layers is significantly reduced. In an ideal
situation, you will be pushed forwards on the compressed layer of
snow instead of getting stuck.
Sufficiently wide volumes, a maximum lifting surface and the
prevention of the anchor effect: these are the requirements for a
highly efficient and modern avalanche airbag. The ABS® TwinBag
system meets these criteria like no other avalanche airbag. The
97% survival rate is the proof.
