Snow cover is given here in snow water equivalent, i.e. the amount of water stored in the snow cover in the mountains. Snow water equivalent is given in millimetres (mm). It is the amount of water bound in the snow cover. The volume of water in millimetres corresponds to the snow load (kg/m2). Snow cover is an important factor influencing Swiss electricity production and thus also indirectly contributing, at least in part, to Switzerland's security of supply.

In terms of content, the snow water equivalent must be closely related to the degree to which Swiss reservoirs are filled. This is because water is stored in the snow, which melts in summer (especially quarter 2 and quarter 3) and fills the reservoirs of the Swiss pumped storage and storage power plants. In addition to snowmelt, however, glacier melt, precipitation in the catchment areas, evaporation associated with high temperatures and many hours of sunshine, and infiltration (seepage) must also be taken into account. Storage lakes are then emptied mainly in winter (quarter 4 and quarter 1) by producing electricity.

Thus, the snow cover in the water equivalent of the current winter can be used to infer the filling possibilities of the storage lakes for the coming winter. However, snow cover is no guarantee for well-filled reservoirs throughout Switzerland, but it is a good prerequisite. In principle, a large snow cover, i.e. a large snow water equivalent, is more likely to fill the reservoirs than a low snow cover.

Disclaimer Data

The snow water equivalent is not tracked between July and October. In these months, the remaining snowmelt amounts are low. The information is obtained from models and incorporated into the data of the existing snow measurement networks.