vastaalkavissa

Vastaalkavissa is a Finnish term that translates roughly to "winter caves" or "snow caves." It refers to temporary shelters constructed from snow and ice, typically during winter expeditions or survival situations in cold climates. These structures are primarily made by excavating snow to create an insulated living space. The density of the snow is crucial, with packed snow offering better insulation than loose powder.

The construction of a vastaalkavissa often involves digging a trench and then creating an arched roof by cutting blocks of snow and ice or by piling snow over a temporary support structure. The entrance is usually kept small and sometimes fitted with a flap to minimize heat loss. The interior can be surprisingly warm due to the insulating properties of snow, which traps body heat and prevents extreme cold from penetrating.

Vastaalkavissa have been used for centuries by indigenous peoples and explorers in Arctic and sub-Arctic regions for protection against harsh weather. They offer a viable alternative to other shelter types when trees or other building materials are scarce. While they provide effective insulation, they also present risks such as carbon dioxide buildup from breathing and potential collapse if not constructed properly or if temperatures fluctuate significantly. Modern survival courses may teach techniques for building such shelters as a basic survival skill.