A computer-based system simulating snowpack structures as a tool for regional avalanche forecasting

Abstract

Abstract This paper describes the current state of a complete automatic system of three numerical models that simulate snovv-cover stratigraphy and avalauchc risks for operational avalanche forecasting. The first model, SAFRAN, estimates relevant meteorological parameters affecting snowpack evolution. The second. Crocus, is a snow numerical model which simulates the physical processes inside the snowpack and its stratigraphy. The last model, MÉPRA, is an expert system; based on an assessment of snowpack stability, it deduces natural and accidental avalanche risks. To describe the great Variability of the snowpack and the associated avalanche risks, this automatic system simulates sriow-cover evolution and its stability for many typical slopes, elevations and aspects representative of the different French massifs. To achieve this result, different kinds of validations have been carried out since winter 1981; they arc mainly based on comparisons with different sets of measurements and on the opinion of users. Although the routinely obtained results do not yet take into account all small-scale effects such as wind transport, they have been considered as valuable information by avalanche forecasters since 1992 93 and used operationally since then.