Skip to content

The 2015 Chileno Valley glacial lake outburst flood, Patagonia

Research output: Contribution to journalArticle

  • R. Wilson
  • S. Harrison
  • J. Reynolds
  • A. Hubbard
  • N. F. Glasser
  • O. Wündrich
  • P. Iribarren Anacona
  • L. Mao
  • S. Shannon
Original languageEnglish
Pages (from-to)51-65
Number of pages15
JournalGeomorphology
Volume332
Early online date8 Feb 2019
DOIs
DateAccepted/In press - 17 Jan 2019
DateE-pub ahead of print - 8 Feb 2019
DatePublished (current) - 1 May 2019

Abstract

Glacial Lake Outburst Floods (GLOFs) have become increasingly common over the past century in response to climate change, posing risks for human activities in many mountain regions. In this paper we document and reconstruct the sequence of events and impact of a large GLOF that took place in December 2015 in the Chileno Valley, Patagonia. Hydrograph data suggests that the flood continued for around eight days with an estimated total discharge of 105.6 × 10 6 m 3 of water. The sequence of events was as follows: (1) A large debris flow entered the lake from two steep and largely non-vegetated mountain gullies located northeast of the Chileno Glacier terminus. (2) Water displaced in the lake by the debris flow increased the discharge through the Chileno Lake outflow. (3) Lake and moraine sediments were eroded by the flood. (4) Eroded sediments were redistributed downstream by the GLOF. The post-GLOF channel at the lake outlet widened in some places by >130 m and the surface elevation of the terrain lowered by a maximum of 38.8 ± 1.5 m. Farther downstream, large amounts of entrained sediment were deposited at the head of an alluvial plain and these sediments produced an ~340 m wide fan with an average increase in surface elevation over the pre-GLOF surface of 4.6 ± 1.5 m. We estimate that around 3.5 million m 3 of material was eroded from the flood-affected area whilst over 0.5 million m 3 of material was deposited in the downstream GLOF fan. The large debris flow that triggered the GLOF was probably a paraglacial response to glacier recession from its Little Ice Age limits. We suggest that GLOFs will continue to occur in these settings in the future as glaciers further recede in response to global warming and produce potentially unstable lakes. Detailed studies of GLOF events are currently limited in Patagonia and the information presented here will therefore help to inform future glacial hazard assessments in this region.

    Research areas

  • Glacial lake, GLOF, Paraglacial response, Patagonia

Download statistics

No data available

Documents

Documents

  • Full-text PDF (final published version)

    Rights statement: This is the final published version of the article (version of record). It first appeared online via Elsevier at https://www.sciencedirect.com/science/article/pii/S0169555X19300224 . Please refer to any applicable terms of use of the publisher.

    Final published version, 9 MB, PDF document

    Licence: CC BY

DOI

View research connections

Related faculties, schools or groups