Reconstruction of the 1989 Laguna del Cerro Largo GLOF: an interdisciplinary understanding of GLOF Impacts

Abstract. The March 16, 1989, glacial lake outburst flood (GLOF) from Laguna del Cerro Largo in Valle Soler, Aysén, Chile, is one of the largest recent moraine-dammed GLOFs in the region. This interdisciplinary approach reconstructs the GLOF downstream impacts using HEC-RAS 2D and GeoClaw from witness accounts. Model results are then validated through field analysis of sediment deposition, dendrogeomorphic surveys, radiocarbon dating. Sediment cores reveal distinct clastic layers attributable to the 1989 event and evidence of an earlier outburst flood from the adjacent Laguna Turbio, dated circa 125 ybp. The model results also indicate a substantially higher peak discharge than official reports, impacting subsequent disaster policy decades later. While dendrogeomorphic sampling was hindered by fungal decay in Nothofagus species, the findings highlight both the potential and limitations of interdisciplinary reconstructions of GLOF events in remote, data-scarce environments.