Grain growth at high temperature gradients, i.e., when excess water vapour density is above a critical value (see also equilibrium growth). Water vapour diffuses from grains showing higher to those ha
ving lower water vapour density, i.e., the so called hand-to-hand mechanism. This process results in the sublimation and deposition or recrystallization of ice as well as changes in crystal size and shape. These changes usually result in a decrease of the specific surface area of snow. Examples of kinetic growth shapes are faceted crystals (FC) and depth hoar (DH)that form within the snowpack, or surface hoar (SH) that grows on the snow surface.