Fresh snow has no strength as a building material. Snow crystals must be broken by patting or stirring. Then the snow will sinter into a mass strong enough to make a roof. We all know how hard a snow bank along a road can be - that's because a snow plow stirred up the snow. The snow crystals have broken into pieces, settled and sintered into a hard mass.

Some backcountry users make a snow shelter by digging into a wind-packed snow slope. It's difficult to judge the inner strength of an existing snow bank of any kind and there is a danger of collapse. A shelter that you build from the ground up can be safer since you can make sure that all the snow is packed properly and sintered enough to form a strong roof.

Keep shoveling snow until the pile is 6 feet high and forms an even dome. It will take about two hours for one person to make the pile. When the pile is finished, you must wait at least one hour to give the snow time to strengthen.

This waiting time is crucial, otherwise you risk a collapse as you build. So, this is a good time to eat a meal or gather spruce boughs if you do not have a sleeping pad to sleep on. Always keep your shovel with you when inside the shelter so that you can dig out if needed. Usually, if a collapse is going to happen, it will happen as you are digging inside. It's best to have one person working inside the shelter and another person outside in case there is a collapse.