Evaluating Unmanned Aircraft Systems for Snow Avalanche Monitoring in Winter Weather and in Mountainous Terrain

The Norwegian Public Roads Administration (NPRA) completed an evaluation of Unmanned Aircraft Systems’ (UAS) ability to operate in winter weather and in mountainous terrain in support of snow avalanche monitoring. Vendors flew nine multi-rotor, rotary-wing, and fixed wing aircraft on four increasingly difficult missions ranging from flights over a nearby road and bridge to a 2.3 kilometer flight to a 1300 meter mountain to inspect avalanche features. Results indicated that there is no single UAS that meets all of the road administration’s needs. The fixed wing aircraft were more capable in bad weather and could fly greater distances to view avalanche release zones. However, they are not always stable camera platforms and required more skill to operate. Multi-rotors were easier to operate and more stable but are less capable in winds and had more limitations when flying to distant features. In general, the photo and video output of the UASs was usable for avalanche assessment. The UAS all flew following the national aviation authority’s line of sight and distance regulations which reduced their ability to travel to out of sight terrain. This suggests that NPRA should work with the authorities to establish permanent danger areas above avalanche zones where beyond line of sight flying is routinely permitted. A multilevel NPRA institutional approach to using UAS was proposed were small multi-rotor aircraft are owned and operated by NPRA and used to look at close-in snow features. For longer flights, fixed wing aircraft flown by a contractors may be the best solution.