Snow

The snow cover maps are created by MetGIS from observations of different satellites and optimised with new snow simulations from weather forecast models. The maps provide information on whether or not snow cover is likely to be present at certain locations, but do not make any statement about snow depth.

Since the satellites used do not fly over Central Europe regularly, the snow information displayed may vary in age depending on the geographical area. The interval between satellite overflights is usually several days. It should also be noted that satellites can only provide snow cover information for cloud-free areas. Therefore, in extreme cases, the information on whether snow is present or not may be a week or older. 

The quality of snow cover maps is highest over open terrain. Over forested areas, the presence of snow cover can often only be insufficiently determined by satellites, as the latter often cannot "see through to the ground", especially in the case of dense vegetation.

The MetGIS fresh snow maps provide information on the forecast amount of new snow (in cm) over a given period of time. To calculate the new snow, MetGIS uses a specially developed algorithm that incorporates high-resolution terrain data into the forecasting process in addition to an accurate determination of the snowfall line.

This calculated value represents the amount of new snow that arrives on the ground during snowfall. There can be a number of reasons why this value deviates from a measured value. For example, the calculation does not take into account the transport of snow by the wind, nor does it take into account melting processes and the settlement of new snow. The last two factors mean that with heavier snowfall and longer reference periods (especially 24 hours and more), the calculated value will often be somewhat greater than the measured value.