Find the Right Site
Choose the site for your snow cave with care. It should be out of the way where skiers might inadvertently happen on it the next morning, and it should not be at the foot of a hill and thus find itself in the path of an avalanche. A clearing surrounded by trees is a good spot to choose for your snow shelter. Another option is a snow drift by a huge boulder.
Pile the Snow
Gather together snow at your building site and pack it down tight. Use a collapsible snow shovel, such as the Burton snow shovel that retails for about $42. The sooner you start the process of building the snow cave, the greater the chance of preventing a snow-cave collapse. The cold air needs to harden the snow, and if you anticipate needing a shelter in the next half hour, you may endanger yourself because this is hardly sufficient time for the air to harden your packed-down mass of snow. When you are finished with the pile, it should represent a 5-feet-tall mass of tightly packed snow.
Tunnel into the Snow
Dig a tunnel into the snow pile that slightly angles upward. Make the hole big enough for you to lie down or sit up in your sleeping bag. Make a hole in the side of the snow cave and prevent its collapse by inserting a rod or hollow piece of plastic. This is your air hole, and if it becomes clogged, you run the risk of having too little oxygen in the snow cave.
Safety Measurements
Check your snow cave to see whether it meets the safety guidelines loosely established by hobbyist mountaineers. As a general rule of thumb, building a snow cave in temperatures of more than 34 degrees F is a risk. The weak spot of a snow shelter is the roof, and while the bottom of the snow cave should be about 2 feet thick, the walls should not measure more than 18 inches in thickness.
