A good shelter is the first thing you need to survive the freezing cold. Choosing your shelter's location is extremely important. Don't be lured in by clearings in the mountains -- they can be prime spots for avalanches. Check for accumulated debris and broken tree stumps at the base of the clearing. If you find both, chances are you're in an avalanche chute. The side of the clearing is a much better shelter location. You should also avoid areas near overlooks and cliffs.
If night is falling fast, you need to build an emergency shelter as soon as possible. Don't get too fancy -- your goal is to make it through the night. Dig a snow trench deep enough to provide a wind break. Pile and pack additional snow on the windy side for further protection. Get as much soft material as you can to line the bottom for insulation -- pine boughs are plentiful in most wooded areas. Once in, cover yourself with copious amounts of pine or any other leaves you can get. Snow is a better insulator than your average tent, so your emergency shelter should get you through the night.
If you have the time, build a more elaborate snow cave. Not only will it provide better protection from the elements, but constructing it will get your heart rate going and warm you up. Just make sure you don't sweat -- moisture is your enemy in the freezing cold. Hillsides provide good wind shelter and low-lying areas are colder and more damp. Make your shelter as small as possible to help retain heat. This is especially true for the entrance, which should be blocked with a backpack or stacked up tree branches.
It's also important to ventilate your shelter. Poke small air holes in the ceiling with tree branches and make sure your blocked entrance allows enough airflow. If you have a cooking stove or lantern, avoid using it inside unless the shelter is extremely well ventilated. It's best to not risk it at all -- carbon monoxide poisoning is a killer in the woods and sneaks up on you fast. Avoid using metal like a plane wing or found tin roofing to aid your shelter -- it will suck up the heat you need.
When you're trapped in the cold and there is no snow, build a debris hut:
- Place a ridgepole, the pole that runs the length of the shelter, with one end on the ground and the other on top of a sturdy base like a tree stump or boulder. You can also lash it to a tree.
- Take two more thick branches and place them diagonally at the top of the ridgepole and lash them together with vine or rope.
- Use thick branches to line the length of the ridgepole to create the ribbed frame. Make sure it's wide enough to accommodate you.
- Place smaller sticks crosswise to make a lattice effect.
- Add lighter soft debris like pine needles and leaves until it's at least two feet thick -- the thicker the debris, the more protection it offers.
- Cover the interior floor with pine and leaves and block the entrance with a rock or more debris.
These are just a couple of examples of wilderness shelters. More can be found in How to Build a Shelter. In the next section, we'll look at how water and your choice of clothing can help you survive the freezing cold.