6.1.8 Hardness, 1
To help determine the stability of a snowpack, we measure the relative hardness of the layers. This refers to the number of bonds per volume, which indicates the degree to which the grains hold together under external pressure.
A very hard layer over a very soft layer decreases stability, while a very soft layer over a very hard layer increases stability.
In the field, a layer’s degree of hardness is defined by the largest object that can penetrate the snow. You can get a quick sense of it by gently pressing objects of varying sizes into the snow and determining the largest object that can penetrate it. In order of increasing hardness, these are a fist, four fingers, one finger, a pencil, and a knife.
