Belvedere, 1951–2023: A Glacier Odyssey

The Belvedere Glacier (Monte Rosa Massif, Italian Alps) has undergone significant transformations over the past seven decades due to climate change and glacial dynamics. This study, conducted within the framework of the 4EU+ cooperation initiative, integrates multi-temporal datasets, including historical aerial photographs, orthophotos, satellite imagery, LiDAR, and drone-based digital elevation models, to investigate surface changes, supraglacial lake evolution, and elevation dynamics between 1951 and 2023. Surface evolution analysis identified three key phases of transformation: 1)the progressive separation of the Nordend Glacier between 1951 and 1991; 2) the partial detachment of the central accumulation basin from 2006 to 2015; 3) the separation of the Locce Nord Glacier observed between 2018 and 2021. A surge event between 1999 and 2002 also contributed to these changes. These processes significantly altered the glacier’s structure, leading to accelerate retreat, especially after the surge event. Mapping of supraglacial lakes revealed a notable increase in their number and area in 2000-2023 timeframe. Lake Effimero, in particular, showed high variability, with its area ranging from 428 m² to 99700 m² between 2000 and 2023. The formation and evolution of these lakes were driven by snowmelt, glacier dynamics, and morphological factors, highlighting their role as indicators of glacial dynamic. Elevation analysis of the debris-covered tongue showed a heterogeneous pattern of downwasting. Between 1951 to 2009, the mean thinning rate was 0.24 m/year. This rate increased to 1.5 m/year between 2009 and 2023, reflecting the consequences of surge event, supraglacial meltwater, and glacial lake outburst floods. All these factors contributed to enhanced thinning and surface modification. This study highlights the value of combining historical and contemporary remote sensing data to assess glacier retreat, lake dynamics, and surface changes. The findings underline the importance of long-term monitoring to understand the impacts of climate change on Alpine glaciers and their associated geomorphological and hydrological processes.