Size independence of the strength of snow.

The mechanical reliability of 600 randomly taken snow samples follows Weibull distributions: If sigma(max) is the maximum stress present in a specimen of given density, the fraction of specimens that fail at stresses below sigma(max) is P=1-exp[-(sigma(max)/sigma(0))(m)]. The scale parameter sigma(0) evaluated by the maximum likelihood method increases nearly quadratically with the density rho of snow, but, unlike predicted by the weakest link model, is independent of size and shape of the specimen: there is no size dependence of the strength of snow. The Weibull parameter m is independent of density, size, and shape of the snow sample, m=1.

Fracture toughness of snow in shear under friction.

The fracture toughness of snow in shear is one of the most relevant parameters when studying the mechanics of snow slab avalanche release. Double-cantilever snow beams were loaded asymmetrically to determine K(IIc). If crack surfaces touch under applied pressure, the fracture toughness in shear of snow (rho=247 kg m(-3)) is K(IIc)=680+/-60 Pa m(1/2).