In the seventies the author carried out numerous laboratory tests, simultaneously performed under six different states of stress and deformation (totally 121 identical three samples tested). The aim was to obtain a three dimensional nonlinear constitutive equation, i.e., one which higher applies to stresses. The theoretical background was a constitutive equation consistent with the principle of maximum entropy production. The irreversible part - which was exclusively considered - depends only on the dissipation function, represented by an exponential series. The final result consists of nine coefficients of three invariants of the stress tensor. Unfortunately, the resulting equation was never used to resolve practical problems in snow mechanics. This paper is aimed to demonstrate the usefulness of the equation by means of simple examples. For a uniform horizontal snow cover, it was firstly shown that snow behaves strongly non-symmetrically under compression and tension. And secondly, it was seen that the settlement (compression) deformation rates are up to 50 per cent higher than those with linear behaviour. In an other example, the development of a shear crack on the occasion of snow slab release has demonstrated that fracture starts earlier upslope and propagates faster than downslope. On the other hand, linearity between shear stresses and shear deformation can be justified.