Recent GLOFs in the Fitz Roy Area, Patagonia, Argentina

Abstract

For the first time, at least five glacial lake outburst floods (GLOFs) have been documented in the Blanco River basin, involving two proglacial lakes—Sucia and Piedras Blancas—located in the Fitz Roy area within the Los Glaciares National Park. This multidisciplinary study combines historical records, aerial photographs, satellite imagery, and geomorphological field evidence—such as boulder size, elevation of boulder bars, lichen cover, and vegetation stripping—together with two-dimensional hydraulic modeling, which enabled the reconstruction of the peak discharges and spatial extent of past GLOF events.We have characterized a previously unreported historical GLOF that occurred between 1966 and 1968 at Sucia Lake, and provide a detailed description for the 1913 outburst flood of Piedras Blancas Lake, which had only been briefly mentioned in earlier studies. Additionally, we have identified three previously unrecognized paleo-outburst floods originating from the same lakes. The identification of five distinct events in a confined sector of the Andes emphasizes the recurrent nature of these catastrophic phenomena and underscores the urgent need for an updated risk assessment. This is particularly relevant considering the increasing number of visitors, as the area includes a dense network of hiking routes, campsites, and accommodation facilities. Understanding the potential impacts of future GLOFs is essential for effective risk management and sustainable tourism planning in this highly visited sector of the Los Glaciares National Park.