Quinzhee

A quinzhee, or quinzee, is a kind of snow shelter made by making a pile of snow, waiting for it to settle together, then hollowing out the inside. In difference, an igloo is made by carefully stacking cut blocks of snow.
It is not easy to make a quinzhee, although it will be warmer and stronger if certain techniques are carefully followed. For strength, the quinzhee needs to be a dome and the lower walls must not support too much weight. The walls should be very thick at the base and get slightly thinner towards to the top of the dome.
For warmth, the entrance of the quinzhee should be a tunnel with an upward sloping floor such that the floor is somewhat higher than the top of the entrance.
Caution: Care must be taken when camping conditions are marginal, such as at temperatures near freezing, or when it is raining. Under these conditions the ceiling of the quinzhee may collapse gradually because the snow is soft. Moreover, the entrance tunnel may become too narrow to permit escape. Hence, under these conditions it is unsafe to spend too much time inside the structure because you may become trapped.