Category: Opinion

Staying warm in the wild isn’t as difficult as most believe. That’s not to say that it is easy

and should be done without some thought and planning. It is just a matter of understanding the forces at work and how to use them to your benefit.

There are 4 primary ways your body loses heat; Evaporation, Radiation, Convection, Conduction. Let’s examine each of these.

1. Evaporation of water from your skin if it is wet (sweating). If your clothing is wet, you will also lose some body heat through evaporation, and through respiration (breathing) when the body temperature is higher than 99°F (37°C). During intense exercise, the body loses 85% of its heat through sweating.
2. Radiation (similar to heat leaving a light bulb). This normal process of heat moving away from the body usually occurs in air temperatures lower than 68°F (20°C). The body loses 65% of its heat through radiation.
3. Convection (this is how a fan cools you, by pulling the heat from you with the air, like wind). The body loses 10% to 15% of its heat through convection.
4. Conduction (such as heat loss from sleeping on the cold ground). Heat is lost in air temperatures lower than 68°F (20°C). The body loses about 2% of its heat through air conduction. However, water causes more heat loss from the body than air does, so heat will be lost from the body very quickly when it is in cold water.

Now that we have identified the four primary causes of heat loss from our bodies, we can prepare ourselves to control each one. This is where the practice of dressing in layers comes from. We choose the material and fit of each layer to provide protection from each of the four enemies to our body heat.

1. Base layer (the one right next to your skin), this layer should be a snug fit, not tight just snug. Moisture management is the job of this layer, it needs to be made of a nonabsorbent wicking material, that moves the moisture away from your skin. Like, polyesters such as Power Dry or Capilene or merino wool, NEVER cotton.
2. Middle layer, this is your insulation layer, I like to have it loose fitting, not baggy, just nonrestrictive. Wool and goose down are fantastic natural insulators. Wool keeps you warm no matter what, while goose down is the most efficient insulator, it is worthless if it gets wet. My Middle layer of choice is a dark-colored, mid-weight, wind-proof fleece, it dries faster than wool and works when wet. It also keeps the biting wind at bay when you take your shell off.
3. Shell layer, this is your protection from the wind, rain and snow. Your shell is your first line of defense, it needs to be waterproof and windproof yet breathable to allow perspiration to escape, you don’t want to freeze in your own sweat. Make sure it is big enough to accommodate your base and middle layers worn together. I prefer one without insulation, with a hood, it is just more versatile out in the wild. Don’t skimp on this one, it is not fun being wet out in the woods, even if you are warm.

You need to do this for both top and bottom, your lower half represents 30-33% of your body mass.

Now we just need to apply the layers judiciously. You will always have your base layer on. If

you are involved in strenuous activity, you will want to remove your middle layer, maybe even your shell top. Just be sure to put them back on when you stop, you want to keep most of the heat you just generated.

When I am out in the winter wonderland I spend most of the time at camp with all three layers on the bottom (I spend a lot of time sitting in the snow) and my base and middle layers on top. this usually keeps me warm enough. You will find your own comfort zone.

Last but not least, we need to take care of out extremities. Head, hands and feet.

1. Head, I spend a lot of time without head-gear, I just run hot. But, I always carry these two things. A Ear-band (a headband designed to cover your ears) and a fleece hat. Combined with the hood on my shell, they have my covered.
2. Hands, I recommend all three layers for these guys. Get yourself a good pair of silk glove liners, worth their weight in gold, not only do they keep your digits toasty, they are fire-proof. A good pair of fleece mittens with matching shells. When you keep all your digits together they are warmer. But, gloves are good too.
3. Feet, These are your most valuable assets, they got you here and they’ll get you out, if you take care of them. Silk sock liners are my personal favorite, but merino wool and polyester work too. Just make sure they fit well, you don’t want these bunching up. Nice mid-weight over the calf boot socks, these work great to join your sock liners with your lower base layer, cozy. A good pair of boots will be your best friend, no one is happier than the person with toasty toes.

Well, there is my seven cents, based on my own personal experience. I have not yet spent a cold miserable night in the wilderness while following these principles. Your greatest tool is your mind. Study these concepts and prepare yourself for the journey, gear doesn’t save your life if you don’t know how to use it. Your body generates all the heat it will ever need. All you need to do, is manage how you lose it, and keep it to a minimum.

I once put a water bottle in my sleeping bag with me, so I would have water in the morning for drinking and coffee, It froze solid overnight. The lesson here, I generate my own heat, so I was never cold. The water bottle however does not, so it froze solid.

As Always,

Stay Vigilant and Be Prepared