Spatial variability of new snow amounts derived from a dense network of Alpine automatic stations

Abstract

AbstractSince 1996, a dense network of Alpine automatic weather and snow-measurement (Interkantonales Mess- und Informationssystem (IMIS)) stations has been in operational use for local and regional avalanche warning. The measurements of the IMIS stations are assumed to be representative for spatially extended regions around the measuring sites for applications in avalanche risk management. In this study, the regional representativeness of these stations with regard to the daily amount of new snow is investigated. The results show that the amount of daily new snow is spatially correlated in a range of ∼5–55 km. Regarding simultaneous observations of daily new snow measurements, which are ∼5–10 km apart, the probability of detection (POD) is given as 0.5±0.03. In this paper, the POD of an automatic warning network is introduced as an indicator of the representativeness of point measurement information for avalanche warning applications. The results of this study may mark a reference value for verification of spatially distributed Alpine meteorological models which evaluate the amount of daily new snow in the Swiss Alps.