Glacial Hazards in Chile: Processes, Assessment, Mitigation and Risk Management Strategies

Glacial Lake Outburst Floods (GLOFs) pose a significant hazard to communities and infrastructure in many mountainous parts of the world, including Chile and a number of other lower income countries. This GLOF hazard has increased over the last century as glaciers recede in response to global climate change forming a growing number of glacial lake systems. Outburst floods can occur anywhere that water is stored beneath or on the surface of a glacier, where water becomes ponded behind an ice front or ice dam, or where water is stored in proglacial lakes that develop between a moraine and a receding glacier margin. Lakes in the latter category (moraine-dammed lakes) are particularly hazardous because a sudden collapse of the moraine dam can trigger the release of large volumes of ponded water. In Peru alone, outburst floods from glacial sources caused ~ 32,000 deaths in the 20th century, as well as destroying vital economic infrastructure, settlements and valuable arable land. In the Nepal Himalaya, it has been estimated that the costs associated with the destruction of a mature single hydropower installation by an outburst flood could exceed USD 500 million. Ice-dammed and moraine-dammed lakes are now developing in Chile as glaciers recede. They pose an ever-increasing threat to communities and infrastructure downstream.

This project will answer questions concerning the past, present and future glacial hazards in Chile. We will assess their changing magnitude, frequency, and distribution under current and future global climate change. We will produce the first complete inventory of historical GLOFs in Chile and identify sites that have the potential to develop glacial hazards in the future. We will use physically-based numerical models to simulate GLOFs at sites identified as posing a high hazard and use these simulations to make hazard and flood risk predictions that can inform planners and decision-makers in Chile and other lower income countries globally.

An important first step towards the assessment of risk attributed to Glacial Lake Outburst Floods (GLOFs) in Chile was the creation of a glacial lake inventory. Using Landsat satellite imagery, glacial lake inventories for 1985, 2000 and 2016 have been compiled allowing an assessment of glacial lake change to be performed in Chile for the first time. Utilising information gained from these inventories, the team were able to identify two sites of interest which were visited in February 2017 during a 3 week field campaign. Of particular interest, the team investigated Lake Chileno which had recently produced a large and destructive flood. The field work included acquiring high resolution aerial photography using drones and measuring lake bathymetry using a newly developed low-cost remote controlled survey boat.