Abstract

Land-to-lake glacier terminus transition can alter glacier dynamics and enhance mass loss. However, the magnitude and timing of dynamic changes during this transition remain poorly constrained, especially in hyperhumid regions such as western Patagonia. We analyze this process at four glaciers by acquired bathymetry data combined with multi-temporal remote-sensing observations to track lake development and glacier retreat. Although each glacier shows distinct patterns, three glaciers underwent marked periods of rapid retreat associated with the onset of buoyant conditions at the termini, while the fourth glacier appears to be entering this stage. Results indicate that during rapid retreat, subaqueous ice loss contributed to 8-40% of total mass loss, underscoring its relevance for glacier mass balance. Based on land-lake contact and dynamics behavior, we propose reclassifying Exploradores Glacier from land- to lake-terminating. The analysis is constrained by the limited spatial coverage of bathymetric surveys, particularly at Grosse and Exploradores Glaciers. Nevertheless, the findings underline the importance of improving bed models and buoyant condition analysis to anticipate glacier changes. Many Patagonian glaciers are expected to evolve into lake-terminating systems, making updated inventories and inclusion of subaqueous mass loss critical for hazard assessment and projections of future ice loss.