In winter, the mountains become a whole new playground for mountain enthusiasts. It’s a sometimes dangerous game where strict safety rules must be followed, but it’s also one that many mountaineering, ice climbing, skiing, snowboarding and snowshoeing enthusiasts look forward to the rest of the year.
Since these disciplines are much more technical than mere summer hiking, most of the people who practice them usually have basic notions acquired through friends, courses, or club or federative activities (this is important, in mountaineering knowledge is transmitted between people). But there is always a first time, a day when you show up in the snow ready to learn; and that day and all those to come (if the activity in question hooks you) should go, at least, dressed accordingly.
The Three Layer Rule
Far from being a rule applicable only in winter, the three-layer rule is a very valid advice also during much of the fall and early spring. Don’t forget that the cold comes early in the mountains and then takes a long time to go away.
As the name suggests, the three-layer rule is to wear three layers on top of each other on the upper body (two on the lower body, depending on the characteristics of the outer garment). This does not mean that we have to carry out the whole activity with the three layers on, but that we can play with them depending on the circumstances, as each of them will fulfill a very specific function:
Also called second skin. It is in direct contact with the body and its function is to keep sweat away from it. This is achieved by means of hydrophobic fabrics, whether synthetic or natural, which “expel” the sweat to the outside, keeping the skin relatively dry.
It is important to note that it is not enough to wear just any tight-fitting garment as a first layer. If we were to use, for example, a cotton T-shirt, it would get soaked with our sweat and cool us down at the stops; a very unpleasant sensation and that has no other solution than to get rid of this garment (something that should not be done in winter in the middle of the mountain). The garments of the first layer must therefore be technical.
As to whether natural fabrics (such as new-generation wool) or synthetics (such as polyester, polypropylene or chlorofiber) are better, the former wick away perspiration better and are more pleasant to the touch, while the latter dry faster and are cheaper.
In addition to being made up of specialized garments, the first layer must be close-fitting, but without being too constricting or disturbing when moving.
The function of the second layer is to insulate us thermally by preventing the heat generated by our body from coming into contact with the cold air outside. The key word here is retention. No warm garment, technical or otherwise, warms by itself; all it does is prevent the air inside from giving up its heat to the outside, just as a wetsuit does with water. It’s an obvious concept, but one that often goes unnoticed; and it has its implications: a warm garment that is too loose will trap a greater volume of air and will be harder to heat, but it will also make it easier for that heat to escape.
Apart from being the right size, a warm garment should be made of a material that loses its insulating and breathability qualities when it gets wet. This material, again, may be synthetic or natural, but is often mixed in order to combine the advantages of both.
Breathability is important, because it is important that perspiration continues its way from our skin to the outside.
The third layer is the one that completes our protection against the outside elements. If the first two layers were more oriented “inwards” (to expel our sweat, keep our warmth), the third layer is oriented “outwards”. Its function is to prevent rainwater or wind from penetrating. Both of these elements, if they find their way inside, have the ability to cool us quickly.
Another desirable feature of this third layer is, once again, breathability. If we can get sweat through it, we will avoid sweat soaking through the inner layers, which can happen even if they are breathable, by simple saturation. The fact is that, as counter-intuitive as it may seem, there are, wonders of nanotechnology, fabrics that are impermeable to rainwater but permeable to our own sweat; a kind of one-way warp.
Now, because of that sort of contradiction, a fabric that meets the characteristics of waterproofness and breathability cannot be perfect in both properties and, eventually, water will eventually get through. Manufacturers label the waterproof level of their garments as “water column”, which can be between 1500 mm and 10,000 mm. Beyond that level, the only thing left to do is to forgo breathability and use a plastic garment.
Finally, the outer garment must be reinforced at critical points and be highly resistant, as most mountain activities will put the resistance of any fabric to the test sooner or later.
The three-layer rule is therefore a basic concept for those who practice any mountain activity. This does not mean that all three layers must be worn at all times during the activity, but it does mean, and this is important, that we must have them all at hand, even in the backpack.