A network of automatic weather and snow stations and supplementary model calculations providing snowpack information for avalanche warning

Abstract

The Swiss Federal Institute for Snow and Avalanche Research (SLF) began to\nconstruct a network of high Alpine automatic weather and snow measurement stations in the Summer\nof 1996. Presently 35 stations are in operation and another 25 stations will be on-line before the\nSummer of 1999. The stations measure wind, air temperature, relative humidity, snow depth, surface\ntemperature, ground (soil) temperature, reflected short wave radiation and three temperatures within\nthe snowpack. The measurements are transferred hourly to the SLF in Davos and the data are used to\ndrive a finite-element based physical snowpack model. The model runs every hour and provides\nsupplementary information regarding the state of the snowpack at the sites of the automatic stations.\nNew snow amounts, settling rates, possible surface hoar formation, temperature and density profiles\nas well as the metamorphic development of the snowpack are all predicted by the model.<BR/>\nThe model is connected to a relational data base which stores the measurements as well as the\nmodel results. New visualization tools are available which allow a fast, easy and comprehensive\naccess to the stored data. The model has been tested in quasi-operational mode during the Winter of\n1997 / 98. The calculation is reliable in terms of the energy budget and the mass balance. The\ndescription of snow metamorphism is currently being improved. The model will be fully operational in\nthe Winter of 1998/99 and will be used by local, regional and national avalanche forecasters.