GEAR - THE CONCEPT OF LAYERING
The next time someone uses the term “layering”, don’t be intimidated or think the
person is just trying to impress you. Layering refers to the different specific layers of
clothing that must be worn when hiking in extreme conditions. Think of the way you
normally dress in terms of layering – you wear underwear and then you wear clothes
over that. Those are two different layers that have different functions. Perhaps you add
a jersey to be warmer - just another layer. In extreme
weather hiking, the choice and order of layers are very
important and the way each layer works is equally
important, not just on its own but also in relation to every
other layer. Layering really matters when the conditions
become tough, so when we speak of layers in the KiliPak, we
do so from the standpoint that it only applies to very cold
hiking conditions. For mild weather, layering is less
important.
When venturing out into extreme weather, there are at least three layers involved to
combat Cold, Wet and Windy conditions - Those are the major forces to contend with
in bad weather, sometimes all of them at once. Now let’s look at each of the individual
layers and see what role they will play to protect us from The Cold, the Wet and the
Windy.
BASE LAYER
As the name implies, the Base Layer is where it all starts, the foundation. The Base
Layer is the first layer worn against the skin and it relies on being in direct contact with
the skin to function properly. This is also why base layers fit snugly around the body.
Usually the particular weave or fabric creates the ability to draw moisture away from the
skin, yet not absorb the moisture into the fabric itself. Instead, the special function of
the Base Layer is to “wick” moisture away from the skin and then to
transport it as far as possible away from the skin, typically towards the
next layer in line, the Insulating Layer. Base Layers are also called
Thermal Underwear, but particular care must be taken when selecting
the Thermal Underwear to ensure that no cotton is used in the
manufacture, but only synthetic fabrics. Cotton tends to trap moisture
in the fabric and this moisture will simply freeze close to the body at
low temperatures making the possibility of Hypothermia quite real. To
function properly, the very fine weave of the Base Layer fabric must be clean and NOT
coated with fabric softeners or body perspiration.
Success Tip: A CLEAN set of Thermal Underwear works best with a CLEAN skin!
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INSULATING LAYER
The first thing to remember about how an Insulating Layer works is that the heat needed
to keep you warm inside the layer actually comes from you! Your body is the primary
heat source on the mountain and it’s that heat that will keep you warm when it gets
cold. Sounds a bit counter-intuitive doesn’t it? Few people consider the fact that their
bodies are heat generators during the normal course of the day
and because of that, they don’t see the benefit of utilising that
heat to stay warm under extreme conditions. The higher the
body’s metabolism or activity level, the more heat is generated
and hence there’s more heat available for staying warm with.
This is basically the mechanism of the Insulating Layer, to trap
warm air so that there is warm air close to and around the
body. The Insulating layer is designed to have tiny air pockets
inside the fabric. Body heat leaves the body and travels
outwards through convective action. As it does so, the air pockets are heated and over
time, there is a heated air layer around the body. This is what keeps us warm. The
insulating layer is typically a Fleece or Down fabric which by design creates these air
pockets. The trick is to actually get the heat to these air pockets, otherwise they won’t
be heated and you won’t get the benefit during the cold nights.
THE OUTER SHELL LAYER
Again, as the name implies, this layer acts as a shell to keep whatever is inside inside,
and whatever is outside, outside. What are we trying to keep in? Well, the warm air that
we’ve trapped inside the Insulating Layer for one. This is the heat we need to stay warm
and the Outer Shell keeps it trapped and close to our bodies.
However, the shell is also designed to keep the wind and wet out so
that we stay dry inside. The main features that an Outer Shell must
possess are: 1. Windproof, 2. Breathable, and 3. “Waterproof”. The
breathing capability is there so that any moisture being generated
inside the layer (body perspiration) can escape to the outside so
that there isn’t a build-up of moisture inside the layer system.
(Remember the risks about moisture explained earlier?) but at the
same time the layer must keep the rain out. This “breathing”
capability causes the layer to not be 100% Waterproof and care
should be taken to distinguish between this layer and a conventional raincoat fabric. The
raincoat fabric by its design must be impermeable and hence it is indeed waterproof. But
it also means that the fabric cannot breathe and hence, whatever moisture is trapped
inside through perspiration will be trapped and have associated risks at high altitude. So,
the breathability makes the fabric slightly less than 100% Waterproof which is why after
some time, depending on the quality of the fabric,
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it will slowly start to allow some moisture through. Therefore, rather think of the Outer
Shell layer as a breathable, windproof and water resistant garment that has a job to do
and then think of adding another totally impermeable layer (such as a Poncho) to
provide the 100% Waterproof-ness.
LAYER SUMMARY
To summarise then, each of the above three layers has a job to do. The Base Layer
keeps you dry and traps some air close to the body. The Insulating Layer traps by far
the most air close to the body and retains the heated air. The Outer Shell Layer keeps
the warm air inside and prevents wind and rain from
entering the system and literally blowing the warm air
away. Only in the correct order can each layer perform
its work properly. When one layer is removed, it’s clear
which function will be removed and how it will impact
you. But, also note that by adding an incorrect layer to
the 3 layers above, you can also destroy the
functionality. Say for example you wish to add a 100%
cotton T-shirt in-between the Base Layer and the
Insulating Layer. What you’ve in effect done is to introduce a layer of fabric close to the
skin which will certainly add some space to trap air (which is why most people think it
will add to warmth), but you’ve also inserted a layer that will trap moisture (perspiration
or rain) and keep that moisture close to the skin. Moisture close to the skin at high
altitude in cold conditions is a dangerous element to contend with.
MAKING IT WORK
To add warmth to this layering system, simply add more air pockets into the Insulating
Layer. Thicker fleece or more down is the logical way. No need to change too much with
either the Base or Outer Shell Layers, the heating portion is the Insulating Layer.
Success Tip: To cool down your house in summer, you open
doors and windows to let cool air in. Do the same on the
mountain when you get too hot by opening the zips and vents
built into the Outer Shell Layer as this will allow hot air to
escape and cool you down. If this is not enough, remove
some or all of the insulating layer which is the storage layer of
hot air. You’ll be surprised how much temperature regulation
you can do by simply making small adjustment to these three
layers.
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