Quantifying frontal disintegration processes at Morteratsch-Pers glacier complex using high-resolution UAV imagery (2017–2025)

Glaciers in the European Alps are retreating and thinning rapidly due to increasing atmospheric temperatures with expected far reaching implications on water availability, biodiversity, and local economy. Given their critical role as freshwater reservoirs and climate indicators, monitoring glacier changes is essential. Uncrewed Aerial Vehicles (UAVs) provide high-resolution, cost-effective observations that bridge the gap between sparse field measurements and coarse satellite data, enabling detailed assessment of glacier surface dynamics. In this study, a UAV- derived high-resolution dataset spanning the years 2017 – 2025 is evaluated to study the frontal spatio-temporal dynamics of the Morteratsch-Pers glacier complex. Surface elevation and surface velocities are derived and combined with reconstructed ice thickness fields (based on radar measurements) to reconstruct the glacier surface mass balance over time. The results are then compared to in-situ stake observations to assess the influence of features such as debris cover and collapsing ice caves, not captured with the local measurements, on frontal retreat patterns.