Measurement of snow depth and avalanche accumulation distribution in avalanche zones using unmanned aerial vehicle photogrammetry with post-processing kinematic positioning

Abstract

In this study, we proposed a method to measure snow depth and avalanche accumulation distribution in avalanche zones by using a small rotorcraft unmanned aerial vehicle (UAV) for avalanche inspection and survey. Snow depth was determined by comparing the differences between the results of a high-resolution digital elevation model (DEM), created by interpolating an aerial laser survey using light detection and ranging (LiDAR) as the elevation of the ground surface, and a digital surface model, created via post-processing kinematic-structure-from-motion with UAV photogrammetry as the elevation of the snow surface. This method provided the snow depth distribution while excluding the effect of vegetation in the avalanche zone. It also showed that a time series of the snow depth distribution can be used to detect the occurrence and expansion of cracks in the snowpack and development of cornice. Moreover, the amount of avalanche deposits can be determined by measuring the snow depth distribution after avalanche occurrence.