Glacial Lake Outburst Floods (GLOFs) in the Cordillera Huayhuash, Peru: Historic Events and Current Susceptibility

Jan Baťka,Eva Štefanová,Vít Vilímek,Simon J Cook,Adam Emmer

doi:10.3390/w12102664

Abstract

The aim of this paper is to create a glacial lake inventory for the Cordillera Huayhuash in Peru and to evaluate the susceptibility of lakes to the generation of glacial lake outburst floods (GLOFs). Using high-resolution satellite images, we undertook qualitative and quantitative analysis of lake type, characteristics and distribution, and placed our findings within the context of existing Peru-wide lake inventories. We also mapped and analyzed past GLOFs, revealing a total of 10 GLOFs and 4 ambiguous events, most of which have not been reported before. We found that past GLOFs usually occurred as a result of moraine dam breach during the proglacial stage of lake evolution. Further, we used our lake inventory to evaluate GLOF susceptibility of all lakes larger than 20,000 m2. Of 46 evaluated lakes, only two lakes (Lake Tsacra and Lake W014) are currently susceptible to generating a GLOF, which would most likely be through dam overtopping resulting from a flood originating in smaller lakes located upstream. The future perspectives of lake evolution and implications for GLOF hazard management are discussed in light of the post-Little Ice Age glacier ice loss as well as in the context of extensive related research undertaken in the nearby Cordillera Blanca.

Highlights

The vast majority of glacierized high mountains have experienced glacier shrinkage in past decades (e.g., [1,2,3])
We focus on glacial lake outburst floods (GLOFs) that have occurred since the Little Ice Age, some 0.3 ka ago [26]
Considering lessons learned from the nearby Cordillera Blanca [44], we suggest that the magnitude of potential GLOFs from currently forming and future bedrock-dammed lakes will likely be lower compared to extreme moraine dam failure-induced GLOFs in the first half of the 20th Century

Summary

Introduction

The vast majority of glacierized high mountains have experienced glacier shrinkage in past decades (e.g., [1,2,3]). Research into GLOFs has grown exponentially in recent years, with increased attention paid to low-income, densely populated mountain regions such as those located in high-mountain Asia (Nepal, India) and the Tropical Andes (Peru, Bolivia) [8]. There is a decades-long tradition of research on glaciers and glacier-related hazard and risks in the Peruvian Tropical Andes (e.g., [9]). As [13] described, the relationship between glacier behavior and climate change is very complicated. It involves glacier characteristics, local morphological conditions (slope, aspect, etc.), local and regional climate and large-scale climate settings

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Conclusion