Positioning of Avalanche Protection Measures Using Snow Depth Mapping via Terrestrial Laser Scanning

In recent years snow depth mapping via terrestrial laser scanning has become increasingly popular as a measurement method used for snow and avalanche research. Due to technological advancements, it is now possible to measure the spatial snow depth distribution on slopes over an area of 4 km2 in a horizontal resolution of 3 cm (at a distance of 100 m), with an accuracy of 5 cm. In this presentation we discuss how the measurement technique was applied to determine the exact positions of permanent, as well as temporary, avalanche protection measures. This includes the positioning of snow fences for snow drift control, the positioning of stabilization structures to control avalanche release and the positioning of blasting devices such as gas explosion tubes or towers from which explosives are ejected. The focus of these investigations lies in the determination of areas with increased snow accumulation due to wind induced snow drift. Locations where such increased snow heights are measured with the laser method and the terrain has a slope inclination exceeding a critical threshold, avalanche releases are to be expected and protection measures should be applied. To precisely determine the most effective position and dimensions of protection measures for preventing or controlling localized snow accumulation on steep slopes, snow depth mapping has been combined with snow drift analysis using basic terrain parameters or wind field modeling to provide additional information regarding the source of the hazardous accumulation to aid decision making. Several case studies in the Austrian Alps are presented and finally the reliability of the presented methodology for positioning and dimensioning of protection measures in alpine terrain is discussed.