Usefulness of mesoscale weather forecast for avalanche forecasting

Avalanche occurrence is a result of the structural collapse of snow cover in the upper reaches of mountainous regions. The collapse may occur either by internal factors related to snow metamorphism or external factors like excessive loading of the snow cover due to snow precipitation, falling of boulders and snow lumps, cornice collapse, explosive waves or seismic activities. Thus to predict an avalanche accurately, an avalanche forecaster is required to keep a continuous record of the weather elements prevailing in the higher reaches which contributes to metamorphism and also the excessive loading of the snow cover due to snow precipitation, cornice formation and its collapse, wind transportation, etc. The information available of the above factors on the synoptic scale, though sufficient for assessment of avalanche danger on a larger scale for a period specific forecast for a general area, is however not sufficient for site-specific and time-specific forecast of an avalanche. This, to a certain extent, can be achieved through mesoscale modelling of various weather parameters using a high-end workstation. This paper describes the genesis of avalanche formation, and the conventional techniques of avalanche forecast in vogue in most of the countries experiencing snow precipitation and avalanches. The paper also brings out how mesoscale modelling of weather parameters can assist in site- and time-specific forecast of an avalanche.