Glacier Surges

Harrison, W. D.; Осипова, Г. Б.; Nosenko, G.; Espizua, Lydia E.; Kääb, Andreas; Fischer, Luzia; Huggel, Christian; Burns, Patty A. Craw; Truffer, Martin; Lai, Alexandre W.

doi:10.1016/b978-0-12-394849-6.00013-5

Cited by 14 publications

(7 citation statements)

References 71 publications

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“…Glacier surges often translate into rapid snout advances (Harrison et al, 2015). The snout of Shisper Glacier started advancing slowly (0.19 m d -1 ) in early 2018 reaching up to 6 m d -1…”

Section: Discussionmentioning

confidence: 99%

The January 2018 to September 2019 surge of Shisper Glacier, Pakistan, detected from remote sensing observations

et al. 2020

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This study analysed the actively surging Shisper Glacier in the Karakoram region of Pakistan using earth observation data from Landsat OLI and Planet images. Changes in the surface glacier velocity, supraglacial moraines and debris cover were assessed using Landsat 8 data at monthly time-steps from January 2018 to May 2019. High resolution data from Planet Labs was used to precisely detect the snout advance and ice-dammed lake expansion. Downstream cross-section profiles of the valley were generated using a moderate resolution digital elevation model to assess the inundation in the event of rapid ice-dammed lake drainage. Correlation Image Analysis Software working on the principle of normalized crosscorrelation was used to generate time series monthly surface velocity profiles for Shisper Glacier. Manual digitization at 1:30000 scale was used to delineate supraglacial moraines and supraglacial debris cover. The glacier surface velocity profiles indicate that the ablation zone of the glacier continues to be in an active surge phase resulting in advance of the snout and expansion of the ice-dammed lake. Surface glacier velocities are as high as 48 m d-1. Between 18 December 2018 and 8 May 2019, the glacier snout advanced at ~6 m d-1 with a total overall advance of 860 m. The lake formed due to damming of outflow stream from Mochowar Glacier expanded to its maximum area (29.69 ha) in May 2019 before drainage started on 23 June 2019. Our estimates indicate that the peak discharge in case of rapid drainage could vary between 5033 m 3 s-1 and 6167 m 3 s-1 and potentially affect infrastructure downstream.

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“…Glacier surges often translate into rapid snout advances (Harrison et al, 2015). The snout of Shisper Glacier started advancing slowly (0.19 m d -1 ) in early 2018 reaching up to 6 m d -1…”

Section: Discussionmentioning

confidence: 99%

The January 2018 to September 2019 surge of Shisper Glacier, Pakistan, detected from remote sensing observations

et al. 2020

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“…Slip of ice over hard beds has diverse consequences. Over periods of up to a few years, some glaciers with hard beds can surge (i.e., increase their speeds commonly by a factor of 10–100) (Kamb, ; Thøgersen et al, ), causing rapid glacier advance and severe local environmental change (Harrison et al, ). Moreover, although large sections of fast‐flowing Antarctic ice streams rest on soft beds, recent geophysical studies of the largest West Antarctic ice stream, Thwaites Glacier, indicate that parts of it are hard‐bedded (Muto et al, ) and drag from slip across hard‐bedded regions is higher than where the bed is soft (Koellner et al, ).…”

Section: Introductionmentioning

confidence: 99%

Sliding Relations for Glacier Slip With Cavities Over Three‐Dimensional Beds

Helanow

Iverson

Zoet

et al. 2020

Geophysical Research Letters

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Results of glacier flow models and associated estimates of future sea level rise depend sensitively on the prescribed relation between shear stress and slip velocity at the glacier bed. Using a fully three‐dimensional numerical model of ice flow, we compute steady‐state sliding relations for where ice slips over a rock bed with three‐dimensional, periodic topography. In agreement with studies of two‐dimensional beds, water‐filled cavities that form down‐glacier from bedforms cause basal shear stress to peak at a threshold slip velocity and decrease at higher velocities (i.e., rate‐weakening drag). However, the shear stress magnitude and extent of rate‐weakening drag depend systematically on lateral topographic variations not considered previously. Moreover, steep up‐glacier‐facing slopes of bedforms can result in shear stress that increases monotonically over a wide range of slip velocity, helping to stabilize slip. These results highlight the potential variability of sliding relations and their likely sensitivity to the morphological diversity of glacier beds.

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“…Identification and monitoring of glacier surges is of particular relevance, since they may pose major hazards. The sudden advance of a surging glacier may lead to river damming (Bruce et al, 1987;Harrison et al, 2015;King, 1934). The newly-formed ice dam may in turn collapse and release a glacial lake outburst flood (Round et al, 2017).…”

Section: Introduction and Previous Studiesmentioning

confidence: 99%

New evidence of glacier surges in the Central Andes of Argentina and Chile

Falaschi

Bolch

Lenzano

et al. 2018

Progress in Physical Geography: Earth and Environment

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In contrast to the large surge-type glacier clusters widely known for several mountain ranges around the world, the presence of surging glaciers in the Andes has been historically seen as marginal. The improved availability of satellite imagery during the last years facilitates investigating of glaciers in more detail even in remote areas. The purpose of the study was therefore to revisit existing information about surge-type glaciers for the Central Andes of Argentina and Chile (32° 40′–34° 20′ S), to identify and characterize possible further surge-type glaciers, providing new insights into the mass balance and evolution of the velocity of selected glaciers during the surge phase. Based on the analysis of 1962–2015 satellite imagery, historical aerial images, differencing of digital elevation models and a literature survey, we identified 21 surge-type glaciers in the study area. Eleven surge events and six possible surge-type glaciers were identified and described for the first time. The estimation of annual elevation changes of these glaciers for the 2000–2011 period, which encompasses the latest surge events in the region, showed heterogeneous behavior with strongly negative to positive surface elevation change patterns (−1.1 to +1.0 m yr−1). Additionally, we calculated maximum surface velocities of 3±1.9 m d−1 and 3.1±1.1 m d−1 for two of the glaciers during the latest identifiable surge events of 1985–1987 and 2003–2007. Within this glacier cluster, highly variable advance rates (0.01–1 km yr−1) and dissimilar surface velocities at the surge peak (3–35 m d−1) were observed. In comparison with other clusters worldwide, surge-type glaciers in the Central Andes are on average smaller and show minor absolute advances. Generally low velocities and the heterogeneous duration of the surge cycles are common between them and glaciers in the Karakorum, a region with similar climatic characteristics and many known surge-type glaciers. As a definitive assertion concerning the underlying surge mechanism of surges in the Central Andes could not be drawn based on the remote sensing data, this opens more detailed research avenues for surge-type glaciers in the region.

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Glacier Surges

Cited by 14 publications

References 71 publications

The January 2018 to September 2019 surge of Shisper Glacier, Pakistan, detected from remote sensing observations

The January 2018 to September 2019 surge of Shisper Glacier, Pakistan, detected from remote sensing observations

Sliding Relations for Glacier Slip With Cavities Over Three‐Dimensional Beds

New evidence of glacier surges in the Central Andes of Argentina and Chile

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