Provided temperatures remain
below 32 degrees F, constructing snow shelters is relatively easy. Sheltering from the
wind is the first priority, since the wind can drastically decrease the air temperature.
Temperatures below 14 degrees F become increasingly unpleasant, so that it becomes
necessary to construct shelters in which heat can be retained extremely well. These can
range from a simple, hollowed-out heap of snow to an igloo, which can take a few hours to
construct. In a long-term shelter, such as an igloo, heavy, cold air can be diverted away
from the occupants by digging a cold sink to channel the air down and away from the
shelter. It is important to allow for adequate ventilation in all snow shelters in order
to prevent suffocation.
||1. Cut blocks from dry, hard,
hard snow, using a snow saw or large knife. Each block should be about 3 ft. (1m) long, 15
in. (40cm) high, and 8 in. (20cm) deep.
||2. Form a circle with blocks
around the hole created where you cut the blocks. Cut the circle in a spiral from the top
of the last block to the ground ahead of the first block. This will make it easy to
construct a dome.
||3. Build up walls, overlapping
the blocks and shaping them so that they lean inward. Cut a hole under the wall for the
cold sink and entrance. Put several blocks along one wall as a sleeping platform.
The last block must initially be larger
than the hole. Place the block on top of the igloo, then, from inside, shape and wiggle it
to slot exactly into the hole.
||5. Hot air
from your body and stove rises and is trapped inside the dome. Cold air falls into the
sink and flows away to the outside. It is essential to cut ventilation holes in the walls
with an ice ax.
With warmth inside the
igloo, the surface of the walls will melt and freeze over, to form a smooth, airtight ice
surface. The roof over entrance tunnel prevents snow from blowing into igloo.
It is vital to make at least one airhole in
the roof to avoid suffocation. The igloo will get very warm inside with heat from your
body, even if it is cold and windy outside. Without ventilation, lethal carbon dioxide
will build up. Also, the use of stoves in an enclosed shelter is not recommended due to
dangerous build-up of carbon monoxide.