Next comes a wool or NRV reducer. Synthetic fleece has many of the same qualities as wool but must be carefully used around a fire since it melts.

Wool and fleece are great insulators but fail to stop wind from reaching the skin, so the next layer needed is a lightweight wind jacket and pants. I recommend nylon or a Gore-Tex type material which allows body moisture to escape while preventing snow and rain from reaching the skin.

The last layer may be the most important. That’s the parka or heavy coat. I recommend a synthetically filled winter coat that goes to the waist or slightly below since a longer coat keeps warmth in the body core where it is needed most.

All these layers trap body heat and moisture. They function best when dry. Allow body moisture to escape by shedding layers when physical activity demands.

One final note about clothing: Raingear goes on every trip with me regardless of the forecast. Moisture robs heat, a loss one cannot afford in the winter.

Ninth rule: Take care of your extremities with the proper hats, gloves and boots.

Seventy percent of heat loss can come from your head, so a good hat must provide warmth and wick moisture. I believe in being prepared and take a musher’s hat, wool watch cap, fleece headband and fleece balaclava.

By taking three pair of wool-fingered gloves, I ensure there’s always a dry pair. Chopper mitts with fleece mitten inserts are used for extreme conditions and collecting firewood.

Footwear is as important as headgear. If your feet freeze you’ll have a rough time getting home. Purchase the warmest and lightest boots available. Buy them big enough for at least two pair of heavy socks with room enough to wiggle your toes.

I take two pair of boots on every winter trip. One is a lightweight mukluk good for –30°. Should these get wet, I can switch to a pair of more waterproof pac boots with felt liners. I carry an extra set of liners that can either go into the mukluk or the pac boot. On several trips I’ve submersed one pair of boots in water and had to switch.

Buy the best quality wool socks on the market. In fact buy four pair and bring them with you. Wear two pair and keep two in reserve. Wear them to bed, as they’ll dry out on your feet while sleeping.