Monitoring glacier evolution and assessing glacial lake outburst flood (GLOF) susceptibility in the Bolivian Andes

Continued deglaciation in the Bolivian Andes threatens regional water security and may result in increased exposure to geohazards. We analyse high spatial resolution (∼3–5 m) satellite imagery to constrain annual glacier and glacial lake evolution across the Bolivian Andes between 2016 and 2022. The total glaciated area of the region decreased by 9.1%, from 316.6 ± 3.2 km2 to 287.8 ± 2.9 km2; a rate of loss of 4.8 km2 a−1. Concurrently, the number (total surface area) of glacial lakes increased by 2.6% (1.9%), from 704 (37.1 ± 0.7 km2) to 770 (37.8 ± 0.8 km2). A comprehensive glacial lake outburst flood susceptibility analysis was undertaken for the 2022 lake inventory,
with eleven lakes identified as ‘high susceptibility’. Subglacial topographic analysis was undertaken to predict potential future sites for lake formation. We identified 55 such sites given continued deglaciation. The model was tested by applying it to areas where glaciers retreated between 2000 and 2022. Of the 22 potentially susceptible lakes which formed during this period, 14 (64%) did so in overdeepenings identified by the model. This is the first time that an inventory of potential future lake sites has been produced for the region.