Abstract Several reported experiments (viz. cohesion of ice spheres, sintering between ice spheres, evaporation from the edge of snow crystals, advancing layers across a growing ice surface, surface electrical conduction in deposited snow) are critically compared and correlated. The temperature dependence of these data below −7°C, analysed with Arrhenius' law, are attributed to thickening of a surface film and migration within that film. The fundamental activation energies are found to be 0.3 eV (release) and 0.4 eV (mobility) on the freshly crystallized basal plane, and 0.6 eV (release) and 0.3 eV (mobility) on annealed surfaces. The energies of sublimation on the basal and prism faces differ markedly.