Experiments and analysis have shown that the ductile compressive yield stress (at -10 ¿C at 4¿10-5 s-1) of S2 saline ice, an orthotropic material whose crystallographic c axes are randomly oriented in the plane perpendicular to the long axis of the columnar grains <Michel, 1978>, loaded triaxially both across and along the columnar-shaped grains obeys Hill's <1950> criterion under low to intermediate levels of confinement. Correspondingly, the ratio of inelastic strains can be described by the attendant associated flow rule. ¿ 1998 American Geophysical Union