though at first glance it seems the least likely structural material imaginable...The insulating value of this shell is further improved by a glaze of ice that the heat of an oil lamp and the bodies of occupants automatically add to the inner surface.
This ice film seals the tiny pores in the shell and, like the aluminum foil on the inner face of modern wall insulation, acts as a radiant-heat reflector. When, finally, the Eskimo drapes the interior of this snow shell with skins and furs, thereby preventing the chilling of this body by either radiant or conductive heat loss to the cold floor and walls, he has completed an almost perfect instrument of control of his thermal environment.