Snow is a geologic material which intermittently covers a large portion of the earth's surface. Since it is a highly porous and thermodynamically active material, previous efforts at characterizing the thermomechanical behavior of the material have not been very successful. Low‐ to medium‐density snow (with void volume fraction in excess of 0.5) is shown to have a very complex set of deformation mechanisms. Such mechanisms as bond growth, intergranular slip, grain deformation, and flexural deformation of crystal chains all are seen to contribute to the total deformation process. When coupled with the nonlinear rheological properties of ice, snow becomes a difficult material to characterize. Special attention is given to the properties of snow when subjected to plastic shock waves. Current methods of analysis are considered and applicability of new continuum theories to this problem are discussed.