A narrow entrance tunnel, a little wider than the occupants of the cave, leads into the main chamber which consists of a flat area, perhaps with elevated sleeping platforms, also excavated from snow. The roof is domed to prevent dripping on the occupants. It is possible to sleep several consecutive nights in a snow cave, but care must be taken since a slight ice surface may develop on the inside of the cave from moisture in the exhaled air of the inhabitants. This is thought to result in reduced air ventilation through the snow cave walls and roof, and thus increase risk of suffocation. A snow cave is a shelter constructed in snow by certain animals in the wild, human mountain climberswinter recreational enthusiasts, and winter survivalists.
In perfect conditions with good snow, digging a snow cave for 2 or 3 persons often takes 3 to 4 hours to complete.