ELUCIDATING SNOW HEIGHT FOR AVALANCHE ASSESSMENT THROUGH AUTOMATED DATA PROCESSING FROM A REMOTELY PILOTED AIRCRAFT SYSTEM AND AUGMENTED WITH AN ADVANCED ROAD WEATHER INFORMATION SYSTEM

Abstract

Remotely piloted aircraft systems (RPAS) and a streamlined photogrammetry process intertwined with an advanced road weather information system (ARWIS) can provide continuous data and information about avalanche precursor conditions. A test case in Atigun Pass, Alaska, above the Arctic Circle, is presented. Wind events that generate large blowing snow quantities are believed to be a significant contributor to avalanches there. RPAS coupled with photogrammetry has been shown to have the potential to improve avalanche risk management. We streamlined the photogrammetry and data processing steps, thereby taking a step forward in unleashing this potential. From an operational and science standpoint, the ARWIS is informative during storms when RPAS cannot fly. Linking RPAS surveys and ARWIS data significantly improves tackling avalanche monitoring challenges. We showed that the ARWIS can monitor blowing snow events and has the potential to serve as a snowdrift monitoring system. Our findings revealed that RPAS surveys can tease out even small changes in snow cover, as well as capture cornice growth and collapse. By coupling RPAS surveys and ARWIS data, we compared two similarly significant blowing snow events; however, only one contributed to significant cornice growth. A comparison of measured temperatures and winds and visual inspection of the snowpack surface showed that extremely cold temperatures and scarred sastrugi surfaces might hinder cornice growth. We also showed that sizeable blowing snow events measured by the ARWIS correlated well with reported avalanches and snowdrifts on the Dalton Highway. Overall, this is the first insight into avalanche precursor conditions in Atigun Pass using an RPAS operated by a ADOT&PF and M&O avalanche forecaster