Regional Mountain Conference

The poster examines the recent geometric and thermal evolution of the Mallory hanging glacier located on the north face of the Aiguille du Midi (Mont-Blanc massif, France). Hanging glaciers are particularly sensitive to climate change because of their steep slopes, small ice volumes, and strong gravitational influence. Recent warming in the Alps has accelerated glacier thinning, thermal and morphological changes, raising concerns about glacier stability and risks for mountaineers.

Using a multi-method monitoring approach, the study combines historical photographs, UAV photogrammetry, terrestrial LiDAR, ground-penetrating RaDAR (GPR) and borehole temperature measurements to analyse glacier dynamics, geometry, and thermal evolution. Results show that the glacier has thinned significantly since the early 2000s, especially in the upper section, where seracs have disappeared and an ice apron has formed. Ice thickness measurements indicate an average thickness of about 20 m, with thinner ice in the upper zone.

Thermal measurements reveal contrasting regimes within the glacier: the upper part remains cold, while the lower part has become polythermal, with seasonal warming driven mainly by meltwater infiltration through crevasses once air temperatures exceed about +2 °C at the Aiguille du Midi. This warming can modify glacier mechanics and potentially influence instability processes, although no clear signs of imminent large-scale collapse have been observed.

Morphological changes have reduced serac activity in some areas but increased exposure of rock and steep ice, altering mountaineering routes near the Aiguille du Midi. While a major ice avalanche remains unlikely, it cannot be completely ruled out, and continued monitoring is necessary to improve risk management and adaptation of high-mountain activities.