Investigating emerging boulder impacts on snowpack ablation

Abstract

The impact of emergent boulders within a thinning and melting snowpack remains poorly understood. Our research examines how boulders, exposed by melting snowpack influence the spatial and temporal patterns of snow ablation in the Shár Shaw Tagà Valley, Yukon, Canada. A multimethod approach, combining thermal infrared time-lapse imaging, drone-based photogrammetry, and terrestrial laser scanning, was used to monitor snow surface temperature, elevation changes, and melt variability. This approach underscores the importance of comprehensive techniques in assessing the spatial and temporal variability of snow surface temperature and topography. Results indicate that boulders accelerate snowmelt in their vicinity during the ablation season, with snow surface thermal characteristics shaped by local terrain and meteorological conditions. The fastest rates of ablation occur during periods of mild weather with no precipitation. These findings highlight the role of boulders as micro-scale heat sources that can modify energy fluxes and influence broader melt patterns in subarctic alpine environments. Understanding these processes is essential for improving snowmelt modelling and predicting hydrological changes in mountain regions affected by climate change.