Snow Avalanche Hazard Assessment Using AHP and Geospatial Techniques for Upper Alaknanda River Basin

This study utilizes Geographic Information System (GIS) based multi-criteria decision analysis to delineate avalanche susceptibility zones in the Upper Alaknanda River Basin of the Western Indian Himalaya. The Analytical Hierarchy Process (AHP) was applied to rigorously assess the relative contribution of eleven critical parameters influencing avalanche initiation and propagation. The selected terrain and environmental factors include slope, aspect, elevation, curvature, topographic roughness index (TRI), topographic wetness index (TWI), Length Slope (LS) factor, land use/land cover, soil, maximum temperature, and Wind Exposition Index (WEI). The terrain-derived parameters were generated from Shuttle Radar Topography Mission (SRTM) data. The Landsat 8 satellite imagery was utilized to evaluate the land use and snowcover information. The database was further complemented with ancillary soil and climatic datasets. A pairwise comparison matrix was constructed to derive weights for each parameter based on expert opinion. The weights were subsequently integrated within the AHP framework to produce an avalanche susceptibility map. The resulting classification reveals that 10% of area under low susceptibility, 56% under moderate susceptibility, 34% under high susceptibility and negligible portion of the basin falls under very low and very high susceptibility. This spatial delineation provides an essential indication base for identifying the most vulnerable zones thereby supporting early-warning systems along with informed land-use planning and hazard mitigation strategies. Furthermore, the susceptibility map can assist in designing structural interventions and implementing controlled avalanche releases to reduce natural hazard risks at selected sites.