Miscellaneous Notes on Camping

Snow is an excellent heat insulating material, comparable to leather and asbestos. The heat of the body quickly warms a small snow structure to the freezing point of water (32° F), provided the snow walls are thick enough (at least one foot), and that all ventilation which is not necessary is excluded.

The amount of fresh air needed for a human being at rest is usually overestimated. Under resting conditions only 0.01 cubic foot of oxygen is consumed each minute. One cubic foot of air per minute for each man is then more than ample. This amount will permeate the unpacked snow around a bivouac. There is then no danger of suffocation from being completely "snowed in" so long as the cave is not glazed with ice.