Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

IF value: 4.713
IF4.713
IF 5-year value: 4.927
IF 5-year
4.927
CiteScore value: 8.0
CiteScore
8.0
SNIP value: 1.425
SNIP1.425
IPP value: 4.65
IPP4.65
SJR value: 2.353
SJR2.353
Scimago H <br class='widget-line-break'>index value: 71
Scimago H
index
71
h5-index value: 53
h5-index53
Preprints
https://doi.org/10.5194/tc-2020-243
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/tc-2020-243
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

  22 Oct 2020

22 Oct 2020

Review status
This preprint is currently under review for the journal TC.

Sudden large-volume detachments of low-angle mountain glaciers – more frequent than thought

Andreas Kääb1, Myléne Jacquemart2, Adrien Gilbert3, Silvan Leinss4, Luc Girod1, Christian Huggel5, Daniel Falaschi6,7, Felipe Ugalde8,9, Dmitry Petrakov10, Sergey Chernomorets10, Mikhail Dokukin11, Frank Paul5, Simon Gascoin12, Etienne Berthier13, and Jeff Kargel14,15 Andreas Kääb et al.
  • 1Department of Geosciences, University of Oslo, Norway
  • 2Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, USA
  • 3Université Grenoble Alpes, CNRS, IGE, Grenoble, France
  • 4Institute of Environmental Engineering, ETH Zurich, Switzerland
  • 5Department of Geography, University of Zurich, Switzerland
  • 6Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales, Mendoza, Argentina
  • 7Departamento de Geografía, Facultad de Filosofía y Letras, Universidad Nacional de Cuyo, Mendoza, Argentina
  • 8Geoestudios, San José de Maipo, Chile
  • 9Departamento de Geología, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile
  • 10Faculty of Geography, M.V.Lomonosov Moscow State University, Moscow, Russia
  • 11High-Mountain Geophysical Institute, Nalchik, Russia
  • 12CESBIO, Université de Toulouse, CNES/CNRS/INRA/IRD/UPS, Toulouse, France
  • 13LEGOS, CNES, CNRS, IRD, UPS, Université de Toulouse, Toulouse, France
  • 14Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, USA
  • 15Planetary Science Institute, University of Arizona, Tucson, AZ, USA

Abstract. The detachment of large parts of low-angle mountain glaciers, resulting in massive ice-rock avalanches, have so far been believed to be a unique type of event, made known to the global scientific community first for the 2002 Kolka Glacier detachment, Caucasus Mountains, and then for the 2016 collapses of two glaciers in the Aru range, Tibet. Since 2016, several so-far unknown glacier detachments have been discovered and described, and new ones occurred. In the current contribution, we compile, compare and discuss 19 actual or possible large-volume detachments of low-angle mountain glaciers at nine different sites in the Caucasus, the Pamirs, Tibet, Alaska’s St. Elias mountains, and the Southern Andes. Many of the detachments reached volumes in the order of 10–100 million m3. Commonalities and differences between the cases investigated suggest that a set of different conditions drives a transient combination of factors related to low basal friction, high driving stress, concentration of shear stress, and low resistance to exceed stability thresholds. Particularly, soft bedrocks below the detached glaciers seem to be a common condition among the observed events, as they offer smooth contact areas between the glacier and its substratum while being prone to till-strength weakening and eventually basal failure under high pore-water pressure. Surface slopes of the detached glaciers range between around 10° and 20°, possibly on the one hand low enough to enable development of thick and thus large-volume glaciers, and on the other hand steep enough to allow critical basal stresses to build up. Most of the ice-rock avalanches resulting from the detachments in this study have a particularly low angle of reach, down to around 0.1 (apparent friction angle), likely due to their high ice content and connected liquefaction potential, the ready availability of soft basal slurries and large amounts of basal water, and the smooth topographic setting typical for glacial valleys. Low-angle glacier detachments combine elements, and likely also physical processes of glacier surges and ice break-offs from steep glaciers. The surge-like temporal evolution ahead of several detachments or their geographic proximity to other surge-type glaciers suggests the glacier detachments investigated can be interpreted as end-members of the continuum of surge-like glacier instabilities. Though rare, glacier detachments appear more frequent than previously thought and disclose, despite local differences in conditions and precursory evolutions, the fundamental and critical potential of low-angle soft glacier beds to fail catastrophically.

Andreas Kääb et al.

Interactive discussion

Status: open (until 17 Dec 2020)
Status: open (until 17 Dec 2020)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement
  • RC1: 'Review', Anonymous Referee #1, 16 Nov 2020 Printer-friendly Version

Andreas Kääb et al.

Andreas Kääb et al.

Viewed

Total article views: 468 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
338 128 2 468 20 2 4
  • HTML: 338
  • PDF: 128
  • XML: 2
  • Total: 468
  • Supplement: 20
  • BibTeX: 2
  • EndNote: 4
Views and downloads (calculated since 22 Oct 2020)
Cumulative views and downloads (calculated since 22 Oct 2020)

Viewed (geographical distribution)

Total article views: 359 (including HTML, PDF, and XML) Thereof 357 with geography defined and 2 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 

Cited

Saved

No saved metrics found.

Discussed

No discussed metrics found.
Latest update: 03 Dec 2020
Publications Copernicus
Download
Short summary
Hardly recognized so far, giant catastrophic detachments of glaciers hold a rare but large potential for loss of lives and massive damage in mountain regions. Several of the events compiled in our study involve volumes (up to 100 million m3 and more), avalanche speeds (up to 300 km/h), and reaches (tens of km) that are hard to imagine. We show that current climate change is able to enhance associated hazards. For the first time, we elaborate a set of factors that could cause these events.
Hardly recognized so far, giant catastrophic detachments of glaciers hold a rare but large...
Citation