  Ice and snow have sometime been classified as a viscoelastic or viscoplastic
mate- rial according to temperature, strain rate, pressure and time scale.
Throughout experimental studies presented in the literature, it has been
observed that at very low temperatures or high strain rate, porous ice and snow
exhibit brittle behavior, but experience high viscous and plastic flow at
temperatures closed to the melting point and low rates. At the macroscopic
level nonlinearity is not necessarily attributed to material level permanent
changes or yielding but mainly to micro cracks, porosity collapse and crack
propagation. This paper attempts to address this complex behavior with a full
microstructure based model.
