The Himalaya, the longest chain of mountains in the world, shows complex variations in snow and meteorological conditions as one traverses from east to west and from south to north. The paper presents the analysis of the past 25 years of snow precipitation and avalanche occurrence data of the Western Himalaya region and delineates the region into three principle zones: Lower, Middle, and Upper. While the Upper Himalaya Zone is close to polar region characteristics, the Lower and Middle Himalaya compares well with the Maritime and Continental Zones. Avalanche forecasting in the Himalayan region is biased towards a conventional knowledge-based approach. The variation in three zones on avalanche activity in the region has been discussed. Different approaches of avalanche forecasting developed so far, however, require experienced observers and forecasters, which causes problems because of the temporary nature of avalanche jobs. It has been seen that each zone warrants separate treatment and models for prediction of avalanches at any one time. (C) 2000 Elsevier Science B.V. All rights reserved.
