Item: Key parameters for local drifting snow events
Title: Key parameters for local drifting snow events
Proceedings: 2010 International Snow Science Workshop
Authors: Gilbert Guyomarc’h and Yves Durand GAME/CNRM – CNRS/Météo-France, Grenoble
Abstract: The transport of snow by the wind is one of the most important processes influencing the accumulation and ablation of the snow in the mountains; this is often the cause of the accidental triggering of avalanches. The Snow Study Centre (specialized research centre of Météo-France) has been working for several years towards upgrading the knowledge on drifting snow and its numerical modelling. In order to obtain this goal, an experimental high altitude site has been set up for the observation of the phenomenon. After several years of in-situ measurements (automatic and manual), a long series of blown snow periods has been observed. These periods (around 15 for each winter season) are well documented by using the recorded parameters eventually completed with human observations and the results of numerical snow pack simulations. For the more recent years, we will show a study about the key parameters of drifting snow events. We will also take into consideration some periods of strong wind without observation of transported snow. In this paper, we will detail the characteristics of the weather conditions (wind speed and direction, precipitation, air temperature, …), the type of surface snow, … which are common to these periods. These key parameters, among others, have been basically used to define the modelling of transported snow used at present time for the forecasting of avalanche hazard into automatic numerical suites.
Keywords: blowing snow modeling, operational avalanche forecasting