Layers

A lot of wonderful things have layers: planets, stars, and lasagna, to name a few.  Aside from making delicious casseroles, layers are also key to keeping warm.  We’ve discussed before the thermodynamic principles of this before, regarding heat transfer, specific heat capacity, and thermodynamic equilibrium, but we are now going to get into the specifics of layering for cold-weather camping (and other outdoor activities).  Remember, layering is as much about staying cool (not sweating) as it is about staying warm, so never be afraid to delayer as you go.

Layer 1 – Base Layer

We discussed base layers briefly in our recent posts, but let’s review here, for completeness’s sake.  A base layer’s main purpose is not to keep you warm, although many will be pretty toasty.  It’s main purpose is to keep water away from your skin, whether that water source is internal or external.  Because base layers are tight-fitting, and usually made from some kind of synthetic material, they don’t trap a lot of air, so they don’t do a lot to keep you warm, although they do keep cold air from being in contact with your skin, so in that respect they can be fairly warming.

Layer 2 – The “Normal” Layer

I call this the normal layer because this is typically where I would wear my regular hiking clothes.  Sometimes, I will switch out the overshirt for something a little warmer, if it’s sufficiently cold outside, but I find that layer means I rarely need any single layer ot be exceedingly insulating.

Layer 3 – The Fuzzy Layer

For whatever reason, I don’t get cold easily.  Perhaps it’s because of my cold-hearted nature, or because I vent a lot of heat, but whatever the case, I will often forgo the fuzzy layer.  However, it’s an important part of the layering system, and should not be neglected in this discussion.  This is where you would wear you fleece-type garments.  In some circumstances, I will go with a fuzzy layer and an outer shell, and skip the puffy layer (which is coming next).  This is one of your key sources of insulation, and really starts to build those layers of trapped, warmable air.

Layer 4 – The Puffy Layer

Hopefully I’m not losing you with these very technical names.  The puffy layer is exactly what it sounds like.  This is your classic, down, winter jacket.  Ideally, you’ll want it to have lots of individual pockets full of down, so that the fluff remains properly distributed (much like in a sleeping bag).  It’s also useful if your puffy layer has vents, since it can get quite warm quite quickly once you start moving.  Sometimes, your puffy layer will also have your outer shell built onto it (especially when it comes to snowpants).

Layer 5 – The Outer Shell

Again, we’ve already discussed this layer before, but to review: the outer shell is some kind of water-resistant/water-repellent/water-proof layer that should also serve as a good wind block (since wind likes to steal away all of those warm layers of air you so painstakingly trapped and heated around yourself).

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It should be noted that you can have multiple of any of these layers, although duplicating the fuzzy layer is the most recommended for additional warmth.  I’ve used this layering system and managed to overheat in -25 degree weather (Fahrenheit), so I can attest that it is quite effective.  Tailor your layering to the cold weather situation in which you find yourself, and remember that staying cool is as important as staying warm.