The 1985 Catastrophic Drainage of a Moraine-Dammed Lake, Khumbu Himal, Nepal: Cause and Consequences

Vuichard, Daniel; Zimmermann, Markus

doi:10.2307/3673305

Cited by 233 publications

(152 citation statements)

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“…The volume of water released by the reconstructed Chukhung GLOF (5-6.5 × 10 6 m 3 ) is smaller than estimated for the Dig Tsho; Vuichard and Zimmerman, 1987) Watanabe and Rothacher, 1996) GLOFs, and is more comparable with estimates for the Nare GLOF (0.5-5 × 10 6 m 3 ; Buchroithner et al, 1982;Fushimi et al, 1985), and for several historical GLOFs in British Columbia (Clague and Evans, 2000;Kershaw et al, 2005). The volume of impounded water is a direct product of moraine-basin morphology and mode of lake development, and the pre-failure water surface elevation.…”

Section: Discussion and Interpretationmentioning

confidence: 99%

“…In many instances, distinct alluvial debris-fans similar to that observed beneath the main breach at Chukhung are located immediately downstream of moraine (Vuichard and Zimmerman, 1987;Evans and Clague, 1994;Kershaw et al, 2005) and landslide dambreaches (Dunning et al, 2006). In both settings, these fans comprise material predominantly sourced from the dam structures themselves, as rapid energy losses immediately downstream of a dam-breach result in the deposition of the coarsest sediment fraction.…”

Section: Discussion and Interpretationmentioning

confidence: 99%

“…Given a triggering event, moraine-breaching may result in a sudden and rapid release of significant volumes of water and sediment (Lliboutry et al, 1977;Vuichard and Zimmerman, 1987;Costa and Schuster, 1988;Evans and Clague, 1994;Walder and Driedger, 1994;Watanabe and Rothacher, 1996;Clague and Evans, 2000;Cenderelli and Wohl, 2001;Kattelmann, 2003;Xin et al, 2008;Osti et al, 2013;Westoby et al, 2014). Such Glacial Lake Outburst Floods (GLOFs) represent a highmagnitude and low-frequency catastrophic phenomenon, and are capable of performing significant geomorphological reworking of moraine, in-channel and overbank environments (Costa and Schuster, 1988;Cenderelli and Wohl, 2003;Kershaw et al, 2005;Breien et al, 2008;Worni et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

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Reconstructing historic Glacial Lake Outburst Floods through numerical modelling and geomorphological assessment: Extreme events in the Himalaya

Westoby

Glasser

Hambrey

et al. 2014

Earth Surf Processes Landf

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Recession of high-mountain glaciers in response to climatic change frequently results in the development of morainedammed glacial lakes. Moraine dam failure is often accompanied by the release of large volumes of water and sediment, termed a Glacial Lake Outburst Flood (GLOF). Chukhung Glacier is a small (~3 km 2 ) receding valley glacier in Mt. Everest (Sagarmatha) National Park, Nepal. Unlike many Himalayan glaciers, which possess a thick mantle of supraglacial debris, its surface is relatively clean. The glacier terminus has receded 1.3 km from its maximum Holocene position, and in doing so provided the space for an icecontact moraine-dammed lake to develop. The lake had a maximum volume of 5.5 × 10 5 m 3 and drained as a result of breaching of the terminal moraine. An estimated 1.3 × 10 5 m 3 of material was removed from the terminal moraine during breach development. Numerical dam-breach modelling, implemented within a Generalised Likelihood Uncertainty Estimation (GLUE) framework, was used to investigate a range of moraine-dam failure scenarios. Reconstructed outflow peak discharges, including failure via overtopping and piping mechanisms, are in the range 146-2200 m 3 s -1 . Results from two-dimensional hydrodynamic GLOF modelling indicate that maximum local flow depths may have exceeded 9 m, with maximum flow velocities exceeding 20 m s -1 within 700 m of the breach. The floodwaters mobilised a significant amount of material, sourced mostly from the expanding breach, forming a 300 m long and 100 m wide debris fan originating at the breach exit. moraine-dam. These results also suggest that inundation of the entire floodplain may have been achieved within ten minutes of initial breach development, suggesting that debris fan development was rapid. We discuss the key glaciological and geomorphological factors that have determined the evolution of a hazardous moraine-dammed lake complex and the subsequent generation of a GLOF and its geomorphological impact.

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Section: Discussion and Interpretationmentioning

confidence: 99%

Section: Discussion and Interpretationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Reconstructing historic Glacial Lake Outburst Floods through numerical modelling and geomorphological assessment: Extreme events in the Himalaya

Westoby

Glasser

Hambrey

et al. 2014

Earth Surf Processes Landf

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“…In 1981, the Zhangzhangbo GLOF in China destroyed a large section of the China-Nepal road, a power station, and a bridge, with losses totalling more than USD 3 million (Bajracharya et al, 2007). The Dig Tso outburst in 1985 destroyed several infrastrucures, land, shops, and the nearly completed Namche Hydropower plant worth USD 3 million (Vuichard and Zimmermann, 1987). In 1994, the Luggye Tso GLOF in Bhutan caused loss of property (Richardson and Reynolds, 2000) and more than 20 lives (Bajracharya et al, 2007).…”

Section: Natural Disastersmentioning

confidence: 99%

Climate Change in the Himalayas: Current State of Knowledge

Gautam¹,

Timilsina²,

Acharya³

2013

Policy Research Working Papers

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“…Triggering mechanisms of these outburst floods include landslides, ice falls, and/or avalanches entering a proglacial lake and resulting in a wave that overtops the dam, leading to dam failure; dam failure due to settlement, piping, and/or the degradation of an ice-cored moraine; heavy rainfall that can alter the hydrostatic pressures placed on the dam; and many others (Richardson and Reynolds, 2000;Carrivick and Tweed, 2016). In the Himalaya, a specific subset of outburst floods called glacial lake outburst floods (GLOFs) has received the most attention with respect to hazards, likely because of their potentially large societal impact (e.g., Vuichard and Zimmermann, 1987). In contrast, glacier outburst floods in the Himalaya, herein referring to outburst floods that are not generated by a proglacial lake, have received relatively little attention likely due to their seemingly unpredictable nature, which has resulted in these events rarely being observed (Fountain and Walder, 1998).…”

mentioning

confidence: 99%

Brief communication: Observations of a glacier outburst flood from Lhotse Glacier, Everest area, Nepal

Rounce

Byers

et al. 2017

The Cryosphere

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Abstract. Glacier outburst floods with origins from Lhotse Glacier, located in the Everest region of Nepal, occurred on 25 May 2015 and 12 June 2016. The most recent event was witnessed by investigators, which provided unique insights into the magnitude, source, and triggering mechanism of the flood. The field assessment and satellite imagery analysis following the event revealed that most of the flood water was stored englacially and that the flood was likely triggered by dam failure. The flood's peak discharge was estimated to be 210 m 3 s −1 . IntroductionGlacier outburst floods occur when stored glacier water is suddenly unleashed. Triggering mechanisms of these outburst floods include landslides, ice falls, and/or avalanches entering a proglacial lake and resulting in a wave that overtops the dam, leading to dam failure; dam failure due to settlement, piping, and/or the degradation of an ice-cored moraine; heavy rainfall that can alter the hydrostatic pressures placed on the dam; and many others (Richardson and Reynolds, 2000;Carrivick and Tweed, 2016). In the Himalaya, a specific subset of outburst floods called glacial lake outburst floods (GLOFs) has received the most attention with respect to hazards, likely because of their potentially large societal impact (e.g., Vuichard and Zimmermann, 1987). In contrast, glacier outburst floods in the Himalaya, herein referring to outburst floods that are not generated by a proglacial lake, have received relatively little attention likely due to their seemingly unpredictable nature, which has resulted in these events rarely being observed (Fountain and Walder, 1998). While they are a known hazard and discussed in the literature (e.g., Richardson and Reynolds, 2000), few studies in Asia have investigated these hazards in detail (Richardson and Quincey, 2009).Glacier outburst floods can occur sub-, en-, or supraglacially when the hydrostatic pressure of the stored water exceeds the structural capacity of the damming body, when stored water is connected to an area of lower hydraulic potential, when englacial channels are progressively enlarged in an unstable manner, and/or when catastrophic glacier buoyancy occurs (Fountain and Walder, 1998;Richardson and Reynolds, 2000;Gulley and Benn, 2007). For debris-covered glaciers, the drainage of supraglacial ponds commonly occurs through englacial conduits, which facilitate connections to areas of lower hydraulic potential (Gulley and Benn, 2007). These englacial conduits develop on debris-covered glaciers in the Himalaya through cut-and-closure mechanisms associated with meltwater streams, the exploitation of high-permeability areas that provide alternative pathways to the impermeable glacier ice, and through hydrofracturing processes (Gulley and Benn, 2007;Benn et al., 2009; Gulley et al., 2009a, b).During the last half-century, debris-covered glaciers in the Everest region have experienced significant mass loss (e.g., Bolch et al., 2011), which has led to the development of glacial lakes and supraglacial ponds (Benn et al...

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The 1985 Catastrophic Drainage of a Moraine-Dammed Lake, Khumbu Himal, Nepal: Cause and Consequences

Cited by 233 publications

References 14 publications

Reconstructing historic Glacial Lake Outburst Floods through numerical modelling and geomorphological assessment: Extreme events in the Himalaya

Reconstructing historic Glacial Lake Outburst Floods through numerical modelling and geomorphological assessment: Extreme events in the Himalaya

Climate Change in the Himalayas: Current State of Knowledge

Brief communication: Observations of a glacier outburst flood from Lhotse Glacier, Everest area, Nepal

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