Layer your clothing and do not wear cotton. This is key in maintaining warmth and staying dry. The base layers you wear next to your body should be moisture-wicking such as Patagonia's Capilene or natural materials such as Ibex's soft merino wool. These help to keep moisture from resting right on your skin and act as the first layer of insulation. Bring several of these layers on a trip so that you can change them when one gets damp.
Wear mid layers that are high in insulation. Fleece, down or materials such as primaloft are good for this layer. These are usually your most bulky layers too but these days companies are making these layers quite packable. A long sleeve mid layer such as Patagonia's R4 pullover and then a fleece or down jacket over that make a good top combination and Mountain Hardwear's Super Power Tights are great for keeping warm during the day. Wear warmer down pants or synthetic equivalent during the night at camp when you are less active.
Wear shell layers if it is at all windy or precipitating. Waterproof and windproof shell jackets and pants are great for skiing or mountaineering. Companies like Arc'Teryx and Patagonia make great shell layers. Because the moisture your body creates while exercising tends to get trapped by these layers you may have to move slower to maintain the dryness of your base and mid layers.
Don't Leave Damp Clothes On
Stay as dry as possible. As soon as you get into camp, change your base layer shirt and hat if it too is damp. Change into your dry, thick camp socks at night before you get into bed or even before you start cooking on the stove. Why not be extra comfortable? Put on your heavy parka layer and make sure to eat enough calories so your metabolism can keep up with generating enough heat. If you don't eat enough, you may end up shivering in the middle of the night.
Wear Your Hat!
Protect your extremities. Wear insulated boots preferably with liners that you can take out of the boot's shell at night and warm with you in your sleeping bag for the next day. Your boots should be waterproof and not too tight. They should fit comfortably with a pair of extra socks. Gloves or mittens (mittens are often warmer) and glove liners should be worn. The most important piece of clothing is your hat however. The majority of heat we lose is through our head and so by wearing a hat, preferably one that reaches so it can cover your ears is a big help.
Stay hydrated. It is much easier than one might think to get dehydrated in the winter. Because the air is colder and may have much less moisture in it than other times of the year your breath instantly evaporates. Wind can also strip the heat from you. In order for our bodies to keep up with staying warm and healthy in such extreme elements it needs to be properly hydrated. Make many hot drinks at night in camp and try as hard as you can to drink water during the day even though it may not be pleasing to drink cold water when it is so cold out. This in conjuntion with proper layering will help to keep you quite warm and dry in the snow.
Article Written By Naomi Judd
Naomi M. Judd is a naturalist, artist and writer. Her work has been published in various literary journals, newspapers and websites. Judd holds a self-designed Bachelor of Arts in adventure writing from Plymouth State University and is earning a Master of Fine Arts in creative writing from the University of Southern Maine.