ABSTRACT
Snow cover is the layer of snow accumulated over a terrain that can suffer a grouping and rearranging process yielding to the production of ice. It remains for a given period of time with variable degrees of metamorphism. It is composed of a solid matrix that hosts a hollow component that can store gases and liquids. Thanks to this structure, snow cover has some physical characteristics such as density, porosity, or hydraulic and thermal conductivity. A peculiarity of snow cover is that its matrix is frozen water. Ice cannot exist at temperatures higher than 0°C. In these situations, the matrix melts and becomes part of the pores. This liquid water can become ice (matrix) again if the temperature is below 0°C. It can also leach into the terrain or become part of superficial runoff. Snow cover, a porous system where the three possible phases of water coexist (gas, liquid, and solid), is a unique element on the Earth’s surface. Also, it is very peculiar because it can experience huge fluctuations, both spatially and temporally. A cyclonic event can increase the extent of snow cover to the order of 1000 km2 (Cohen and Rind 1991).
