Avalanche susceptibility mapping using geospatial modelling in the Nubra Valley, Trans-Himalaya

Avalanches pose significant risks in snow-covered mountains, impacting settlements and infrastructure. This study focuses on mapping avalanche susceptibility in the Nubra–Shyok region of Ladakh, Trans-Himalaya using geospatial techniques and the Analytical Hierarchy Process (AHP). An inventory of 73 avalanches, compiled from Google Earth Pro and historical records, validated the susceptibility maps. Findings indicate that elevations between 5000 and 6000 m represent the most avalanche-prone zone, with 62% of avalanches occurring in this range. Slopes between 30° and 40° accounted for 43% of events, while those above 45° were less affected (12%). Most avalanches (48%) occurred on north- to northeast-facing slopes, with convex slopes being more prone (33%). Seasonal patterns revealed that 37% occurred in March during snowmelt. Additionally, 67% of avalanches were on barren or snow-covered land, particularly over weak and highly fractured lithological units corresponding to Paleozoic and Cretaceous formations (44%). The map identified 30% of the region as high-susceptibility and 10% as very high-susceptibility, especially along glacier valleys and northern ridges. The validation showed that 80% of mapped avalanches fall within high and very high susceptibility zones, with an Area Under the Curve (AUC) value of 0.83, indicating strong predictive performance and offering a replicable approach for avalanche susceptibility management in similar high-altitude environments.