Staying Warm on the Trail
It’s about dead air and moisture control
by Jerry Raychel
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Keeping yourself warm on the trail
It is a lot like keeping the inside of your house warm

Your house:

Your house has a furnace. - The heat generated by the furnace needs to be contained in a vessel that limits its conductance away and prevents infiltration of cold air inside.

Your house has an insulation layer. Its purpose is to trap dead air, which is the best insulator or in other words a poor conductor. The insulation generally consists of a lightweight material fiberglass or polystyrene etc with lots of tiny pockets of dead air. A good insulation layer limits heat loss by conductance. For any given insulation material the thicker the layer the less the heat loss.

Your house has a vapor barrier; it controls interior generated moisture to keep the insulation dry. The reason is simply that those air pockets collapse and compress when wet or fill with moisture which is a much better conductor of heat than dead air.

Your house has a roof to control exterior moisture and prevent it from having the same effect on the insulation as the interior generated moisture.

The combination of a good tight construction job on the exterior and interior walls and roof, the wrap on the outside, the vapor barrier and the insulation prevent heat loss by the other major mechanism- infiltration.

You:

Your body is your furnace.-You need to keep your self well fed and hydrated to keep the furnace generating heat.

The way you dress while on the trail, on the runners, around camp or in the sleeping bag is all about minimizing the heat loss your body experiences from either conduction or infiltration and one other mechanism: evaporation. You need to keep a layer of dead air around you to limit conductance, you need to control the internally generated moisture (perspiration), the externally generated moisture rain and snow so that the insulation remains a poor conductor and you need to prevent unwanted infiltration. Simple.

Foundation:

You build a house from the ground up so lets start with cold weather footgear.

Socks:
Might as well say it now cotton kills. The reason it is a poor choice is that it absorbs water filling the airspaces and providing good conductance. Use wool or synthetic as they tend to stay drier. There are vapor barrier socks (sealskins?) which could prevent foot perspiration from reaching the socks. I’ve never used them but I would bet that you wouldn’t want to wear them for long periods of time. Trench foot doesn’t only happen in the jungle. More later.

Boots:

Three basic concepts:

So what’s best? Life’s a compromise. I take bunny boots and mukluks on extended trips and I save the pac boots for day trips.

The Walls:

Here the house comparison has a flaw. I don’t think I’ve ever seen anyone wear a vapor barrier suit to keep perspiration from compromising insulation. Interior moisture control here is provided in a number of other ways.

First- by wearing insulator materials that maintain their poor conductance when wet or wick moisture away from the insulation near the body to the outside or at least near the out side of the insulating layers. If cotton kills, synthetics save.

Second- by dressing in layers that can be added or removed as activity level changes to prevent generation of excess perspiration. I quit buying heavy parkas and snowsuits years ago. Besides being too warm for many conditions they are bulky and hard to run in. My extreme cold weather outfit includes a layer of medium weight synthetic material long johns, polar fleece pants and top, a synthetic filled vest, a medium weight synthetic filled parka, a lightly insulated anorak and a pair of wind pants. I wear them in whatever combination is right for the conditions and my activity level. Remember when buying to get larger sizes as you work outward. My anorak is a tall xxl and I’m sure not.

Third- by controlling your activity level so that you don’t work up a sweat if you’re going to be outside for an extended period of time. Easier said than done but keep it as a goal.

A few words about infiltration. You need a wind proof outer layer if you’re going to be out in open country or even if your dog team just goes really fast. A Gore-Tex outer layer (or some other water resistant breathable material) works well here if you think rain or wet snow is an issue. Give plenty of thought to zippers. They’re a pain to work when it is really cold out and that wind can find it’s way through those zippers to your body with surprising ease. Zippers are also subject to icing up. Pay special attention to the neck area. Neck gators are great. I prefer pullover style shirts and parkas and elastic or drawstring waist pants.

The Roof:

It’s pretty well known that wearing a decent hat is major factor in staying warm. If you want to cool down in a hurry take it off. Those musher style hats with outer shells of Gore-Tex or nylon and linings of polar fleece are great. They’re light weight, warm and they cope well with interior and exterior moisture.

If you haven’t tried a good fur hat you don’t know what a warm head is. I have a beaver hat that I had to quit wearing on distance races. In my fatigued state I’d get so comfortable in it, I’d fall asleep. The disadvantage is weight and it doesn’t deal as well with moisture. Then of course there are the social/ cultural issues.

Aside from a hat you need something to protect your face. I’ve tried various neoprene and other fancy facemasks but my favorite is the polar fleece neck gator. They’re light, cheap and you can rotate them around your head as one area gets iced up.

Finally a good parka hood with a fur ruff will create a dead air space in front of your face that is surprisingly effective even in a head wind if properly adjusted.

Outbuildings:

All right this is a stretch but your hands are kind of out there away from the furnace. For that reason in extreme conditions, I find they need a little supplemental heat. I like to put those chemical heat packs inside thermax glove liners. You can do all the fine motor things you need to do like putting on booties, working snaps and working zippers without directly exposing your flesh to the weather or cold metal. If you’ve ever grabbed your snow hook or a dog food pan bare handed at 20 below zero you’ll know why these liners are a must. They can be worn easily inside a thick pair of synthetic insulated mittens when you’re just riding on the sled. The mittens should be worn on an idiot strap so they can be shed in a hurry without fear of loss. On my first Iditarod, I found myself wandering around several villages trying to purchase a new pair of mittens because I’d lost mine on the trail.

The Bedroom:

If cotton kills, and synthetic saves, then down is deadly. While a down sleeping bag can be extremely warm when dry, it can’t be reliably kept that way on an extended camping trip. Get a good synthetic bag rated for 30 below or so. Don’t rely on the manufacturers rating either. Talk to your friends and get their opinions. Look for a bag that has plenty of loft (i.e. thick insulation). Get one that is big enough that you can get into it fully clothed in an emergency. Consider a Gore-Tex over bag to keep exterior moisture out. Bring a good ground pad.

Ideally your sled bag should be big enough to sleep in if your not carrying a tent. People cut corners here on distance races all the time to reduce weight. In my opinion that is a huge risk.

Equipment List:
CAMPING WITH SLED DOGS EQUIPMENT LIST
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