Flooding Glacial Lakes in Chile

It is a peaceful experience to walk near the glacial lake near Colonia Glacier, one of several prominent glacier lakes in Patagonia, Chile. The breeze on the lake helps you relax as you look out on the distant glaciers. In such a tranquil setting, it is hard to imagine that a glacial lake outburst flood (GLOFs) could pose a threat to the area. However, GLOFs have become a significant but poorly understood hazard of a warming global climate.

Glacial Lake near Colonia Glacier (source: Ben Price / Flickr).

The truth is, melting Colonia Glacier, located in the Northern Patagonian Ice Field, Chile, has caused dozens of GLOFs over the years. The lake near Colonia Glacier, Cachet II, has been drained frequently after unexpected floodings. The people living nearby are under constant threat of a sudden flood, which could completely destroy homes and livelihoods.

Actually now, in the Chilean and Argentinean Andes, recent research by project member Pablo Iribarren Anacona has identified at least 31 glacial lakes have failed since the eighteenth century, producing over 100 GLOF events.

Comparison of 1987 and 2015 Landsat images indicating Colonia Glacier retreat and the development of a new lake at the terminus (source: Mauri Pelto/AGU).

“These lakes can be dangerous, and we need to take action,” Alton Byers, a geologist at the University of Colorado, told GlacierHub.

A group of scientists concerned about GLOF risk have initiated a project, “Glacier Hazards in Chile,” which aims to answer key questions concerning past, present and future glacial hazards in Chile. One of the members is Ryan Wilson, a glaciologist at Aberystwyth University in the United Kingdom.

Glacier lake outburst flooding (source: Pieter Edelman/Flickr).

“The project will assess the changing magnitude, frequency, and distribution of different glacial hazards in Chile under current and future global climate change,” Wilson explained to GlacierHub. At the moment, Wilson and the other researchers are focusing on understanding the processes that govern the development of GLOFs in Chile.

The fieldwork of Wilson and his team was recently featured in Science. The them held a workshop at Aberystwyth University in July 2016, during which they discussed progress on their Chilean fieldwork, glacial lake mapping, glacial hazard assessment, outburst flood modeling and climate modeling.

Left to right: Marius Schaefer, Ryan Wilson, Neil Glasser, John Reynolds, Sarah Shannon, and Pablo Irribaren (source: Glacial Hazards in Chile).

To assess GLOFs and GLOF risk, the team compiled a glacial lake inventory for the central and Patagonian Andes (1986 – 2016). Wilson said they used remote-sensing and fieldwork to find past GLOF sites around the major icefields, satellite glaciers and snow-and ice-capped volcanoes of Chile.

A storm is brewing (source: Joost van Veen/Flickr).

“We have managed to use this lake inventory to inform field campaigns in February to two interesting glacial lake sites in Chile,” Wilson said. “We conducted aerial drone surveys and collected lake bathymetry data.” The team will next analyze flood hydrographs (a graph showing the rate of flow versus time past a specific point in a river) of selected former GLOFs and use these to establish the patterns of downstream impacts. They are proud of their work so far, which they hope to publish soon.

The team carrying out a topographic survey in the Colonia Valley (source: Glacial Hazards in Chile).

Using the inventory across Chile, the team and local community  are able to assess the potential damage GLOFs can cause. Wilson et al. plan to “conduct numerical simulations of downstream impacts for selected potential GLOF sites using physically-based numerical flood models.”

In collaboration with Chilean partners, this research will be used to develop early warning systems and raise awareness about quantified GLOF risks. Glacial hazards have threatened various commercial and governmental stakeholders across Chile, making GLOFs a pressing priority.

Lalo, a local farmer who raises livestock, is under the threat of GLOFs (source: NRDC).

The ultimate goal of the project is to provide a framework that can be applied to other lower income countries, since GLOFs pose threats in multiple countries.

“We will make recommendations for GLOF hazard assessment protocols and mitigation strategies in lower income countries globally,” Wilson told GlacierHub.

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