Hydrologic and geomorphic changes resulting from episodic glacial lake outburst floods: Rio Colonia, Patagonia, Chile

Geophysical Research Letters
By: , and 

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Abstract

Glacial lake outburst floods (GLOFs) are a prominent but poorly understood cryospheric hazard in a warming climate. We quantify the hydrologic and geomorphic response to 21 episodic GLOFs that began in April 2008 using multitemporal satellite imagery and field observations. Peak discharge exiting the source lake became progressively muted downstream. At ~40–60 km downstream, where the floods entered and traveled down the main stem Rio Baker, peak discharges were generally < 2000 m3 s−1, although these flows were still >1–2 times the peak annual discharge of this system, Chile's largest river by volume. As such, caution must be applied to empirical relationships relating lake volume to peak discharge, as the latter is dependent on where this observation is made along the flood path. The GLOFs and subsequent periods of free drainage resulted in > 40 m of incision, the net removal of ~25 × 106 m3 of sediment from the source lake basin, and a nonsteady channel configuration downstream. These results demonstrate that GLOFs sourced from low‐order tributaries can produce significant floods on major main stem rivers, in addition to significantly altering sediment dynamics.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Hydrologic and geomorphic changes resulting from episodic glacial lake outburst floods: Rio Colonia, Patagonia, Chile
Series title Geophysical Research Letters
DOI 10.1002/2016GL071374
Volume 44
Issue 2
Year Published 2017
Language English
Publisher American Geophysical Union
Contributing office(s) Alaska Science Center, Alaska Science Center Water
Description 11 p.
First page 854
Last page 864
Country Chile
Other Geospatial Cachet‐Colonia‐Baker Valley, Patagonia, Rio Colonia
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