Human-centered avalanche susceptibility mapping (H-CASM): shifting the cartographic emphasis of backcountry avalanche susceptibility maps

Abstract

ABSTRACT With backcountry winter travel increasing in popularity, the importance of accessible avalanche safety information is crucial. Widely accessible avalanche backcountry maps use slope shading to show where avalanches are likely to start. This paper presents a new methodology called Human-Centered Avalanche Susceptibility Mapping (H-CASM), which shifts the cartographic emphasis of backcountry avalanche maps from the hazard of an avalanche starting in a specific location to risk to a human traveling in the terrain. Utilizing ArcGIS, RAMMS avalanche runout model, and Python, we developed H-CASM as an open-source code to incorporate possible avalanche runouts, terrain traps, and connected slopes while trying to reduce instances of false certainty in visualizations. To provide a more comprehensive representation of susceptible terrain, we integrated aspect, distance to ridges, and vector ruggedness in addition to slope for start zone susceptibility using high-resolution one-meter Digital Elevation Models (DEMs). Avoiding the use of discrete susceptibility categories, we applied continuous gradient shading reducing false certainty in the final visualization. This proof of concept sets a new precedent for the future of backcountry avalanche susceptibility maps.