Modeling of the largest snow avalanche tragedy in the Western Carpathians (Veľká Fatra Mountains – Slovakia)

On February 6, 1924, a catastrophic snow avalanche struck the settlement of Rybie in the Veľká Fatra Mountains, remaining the deadliest avalanche disaster on record in Slovakia and the entire Western Carpathians, with 18 fatalities. Historical documentation offers limited quantitative data on the event's parameters, including release zone locations and snow depths, although the positions of destroyed buildings can still be partially identified in the field. Leveraging recent advances in high-resolution terrain data (e.g., LiDAR), GIS-based tools for identifying potential release areas (PRA), and dynamic simulation models (AvaFrame and RAMMS::Avalanche), this study performs a back-calculation of the 1924 avalanche. A series of simulations were conducted based on delineated PRAs and analyzed against a critical destructive pressure threshold of 20 kPa at the locations of the former buildings. The results identify an avalanche with a crown height of at least 1.6 m as the most probable scenario. These findings contribute to the reassessment of the site's future avalanche vulnerability and provide a methodological contribution to avalanche modeling and historical accident reconstruction.