Geomorphological analysis and identification of threats associated with climate change in the Torrecillas Glacier basin, Los Alerces National Park, Patagonia Argentina

Abstract

In the Torrecillas Glacier watershed, located in the North Patagonian Andes, in the Parque Nacional Los Alerces, paraglacial processes that are introducing essential changes in the area have been identified. The glaciology and geomorphology of this sector are complex, characterized by the coexistence of a free glacier at the headwaters and a debris-covered glacier downstream within a watershed exhibiting significant geomorphological activity. The past and present morphodynamics of this area have been studied to identify possible future behaviors, especially those related to Glacial Lake Outburst Flow events. Field control and the analysis and comparison of temporal satellite images, aerial photographs and Digital Elevation Model allowed the recognition of the rapid retreat of the covered glacier in the last 14 years and the development of a greater intensity of paraglacial phenomena. Besides, in recent years a Glacial Lake Outburst Flow type event was caused by the sudden entry of more than 12.000 m³ of debris, snow, and ice into the proglacial lake. Precipitation and temperatures above the average are being proposed as the triggering factor. Additionally, the detailed study of the Glaciar Torrecillas watershed allowed the recognition of threatening areas. Due to rising temperatures and decreasing precipitation in the last decades, and the short-term climate variability registered in the area, it is necessary to study and monitor unstable sites to detect gravitational phenomena.