Articles | Volume 15, issue 7
https://doi.org/10.5194/tc-15-3539-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/tc-15-3539-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
30 Jul 2021
Research article |
| 30 Jul 2021
| 30 Jul 2021
Dynamic crack propagation in weak snowpack layers: insights from high-resolution, high-speed photography
WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland
Alec van Herwijnen
WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland
Benjamin Reuter
Météo-France, CNRS, CNRM, Centre d`Etudes de la
Neige, Grenoble, France
Grégoire Bobillier
WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland
Jürg Dual
Institute for Mechanical Systems, ETH Zurich, Zurich, Switzerland
Jürg Schweizer
WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland
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Antoine Guillemot, Alec van Herwijnen, Eric Larose, Stephanie Mayer, and Laurent Baillet
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Ambient noise correlation is a broadly used method in seismology to monitor tiny changes in subsurface properties. Some environmental forcings may influence this method, including snow. During one winter season, we studied this snow effect on seismic velocity of the medium, recorded by a pair of seismic sensors. We detected and modeled a measurable effect during early snowfalls: the fresh new snow layer modifies rigidity and density of the medium, thus decreasing the recorded seismic velocity.
Nora Helbig, Michael Schirmer, Jan Magnusson, Flavia Mäder, Alec van Herwijnen, Louis Quéno, Yves Bühler, Jeff S. Deems, and Simon Gascoin
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Jürg Schweizer, Christoph Mitterer, Benjamin Reuter, and Frank Techel
The Cryosphere, 15, 3293–3315, https://doi.org/10.5194/tc-15-3293-2021, https://doi.org/10.5194/tc-15-3293-2021, 2021
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Snow avalanches threaten people and infrastructure in snow-covered mountain regions. To mitigate the effects of avalanches, warnings are issued by public forecasting services. Presently, the five danger levels are described in qualitative terms. We aim to characterize the avalanche danger levels based on expert field observations of snow instability. Our findings contribute to an evidence-based description of danger levels and to improve consistency and accuracy of avalanche forecasts.
Michaela Wenner, Clément Hibert, Alec van Herwijnen, Lorenz Meier, and Fabian Walter
Nat. Hazards Earth Syst. Sci., 21, 339–361, https://doi.org/10.5194/nhess-21-339-2021, https://doi.org/10.5194/nhess-21-339-2021, 2021
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Mass movements constitute a risk to property and human life. In this study we use machine learning to automatically detect and classify slope failure events using ground vibrations. We explore the influence of non-ideal though commonly encountered conditions: poor network coverage, small number of events, and low signal-to-noise ratios. Our approach enables us to detect the occurrence of rare events of high interest in a large data set of more than a million windowed seismic signals.
Bettina Richter, Alec van Herwijnen, Mathias W. Rotach, and Jürg Schweizer
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We investigated the sensitivity of modeled snow instability to uncertainties in meteorological input, typically found in complex terrain. The formation of the weak layer was very robust due to the long dry period, indicated by a widespread avalanche problem. Once a weak layer has formed, precipitation mostly determined slab and weak layer properties and hence snow instability. When spatially assessing snow instability for avalanche forecasting, accurate precipitation patterns have to be known.
Frank Techel, Karsten Müller, and Jürg Schweizer
The Cryosphere, 14, 3503–3521, https://doi.org/10.5194/tc-14-3503-2020, https://doi.org/10.5194/tc-14-3503-2020, 2020
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Louis Quéno, Charles Fierz, Alec van Herwijnen, Dylan Longridge, and Nander Wever
The Cryosphere, 14, 3449–3464, https://doi.org/10.5194/tc-14-3449-2020, https://doi.org/10.5194/tc-14-3449-2020, 2020
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Deep ice layers may form in the snowpack due to preferential water flow with impacts on the snowpack mechanical, hydrological and thermodynamical properties. We studied their formation and evolution at a high-altitude alpine site, combining a comprehensive observation dataset at a daily frequency (with traditional snowpack observations, penetration resistance and radar measurements) and detailed snowpack modeling, including a new parameterization of ice formation in the 1-D SNOWPACK model.
Cited articles
Alfarah, B., López-Almansa, F., and Oller, S.: New methodology for calculating damage variables evolution in Plastic Damage Model for RC structures, Eng. Struct., 132, 70–86, https://doi.org/10.1016/j.engstruct.2016.11.022, 2017.
Bair, E. H., Simenhois, R., van Herwijnen, A., and Birkeland, K.: The influence of edge effects on crack propagation in snow stability tests, The Cryosphere, 8, 1407–1418, https://doi.org/10.5194/tc-8-1407-2014, 2014.
Bergfeld, B., van Herwijnen, A., Bobillier, G., and Schweizer, J.: Measuring slope-scale crack propagation in weak snowpack layers, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8369, https://doi.org/10.5194/egusphere-egu2020-8369, 2020.
Bergfeld, B., van Herwijnen, A., Reuter, B., Bobillier, G., Dual, J., and Schweizer, J.: Dataset for “Dynamic crack propagation in weak snowpack layers: Insights from high-resolution, high-speed photography”, EnviDat, https://doi.org/10.16904/envidat.231, 2021.
Birkeland, K. W., van Herwijnen, A., Reuter, B., and Bergfeld, B.: Temporal changes in the mechanical properties of snow related to crack propagation after loading, Cold Reg. Sci. Technol., 159, 142–152, https://doi.org/10.1016/j.coldregions.2018.11.007, 2019.
Bobillier, G., Bergfeld, B., Dual, J., Gaume, J., van Herwijnen, A., and Schweizer, J.: Micro-mechanical insights into the dynamics of crack propagation in snow fracture experiments, Sci. Rep., 11, 11711, https://doi.org/10.1038/s41598-021-90910-3, 2021.
Bradski, G. and Kaehler, A.: Learning OpenCV, O'Reilly Media Inc., Sebastopol, 2008.
Broberg, K. B.: How fast can a crack go?, Mater. Sci., 32, 80–86, https://doi.org/10.1007/BF02538928, 1996.
Fierz, C., Armstrong, R. L., Durand, Y., Etchevers, P., Greene, E., McClung, D. M., Nishimura, K., Satyawali, P. K., and Sokratov, S. A.: The International Classification for Seasonal Snow on the Ground, HP-VII Technical Documents in Hydrology, IACS Contribution no. 1, UNESCO-IHP, Paris, France, 90 pp., 2009.
Gaume, J., van Herwijnen, A., Gast, T., Teran, J., and Jiang, C.: Investigating the release and flow of snow avalanches at the slope-scale using a unified model based on the material point method, Cold Reg. Sci. Technol., 168, 102847, https://doi.org/10.1016/j.coldregions.2019.102847, 2019.
Gauthier, D. and Jamieson, J. B.: Towards a field test for fracture propagation propensity in weak snowpack layers, J. Glaciol., 52, 164–168, https://doi.org/10.3189/172756506781828962, 2006a.
Gauthier, D. and Jamieson, J. B.: Evaluating a prototype field test for weak layer fracture and failure propagation, Proceedings ISSW 2006, International Snow Science Workshop, Telluride CO, USA, 1–6 October 2006, 107–116, 2006b.
Greene, E., Birkeland, K., Elder, K., McCammon, I., Staples, M., and Sharaf, D.: Snow, Weather, and Avalanches: Observation Guidelines for Avalanche Programs in the United States, 3rd ed., American Avalanche Association, Victor ID, USA, 104 pp., 2016.
Gross, D. and Seelig, T.: Bruchmechanik, 3rd ed., Springer, Berlin, Germany, 317 pp., 2001.
Hamre, D., Simenhois, R., and Birkeland, K.: Fracture speeds of triggered avalanches, Proceedings ISSW 2014, International Snow Science Workshop, Banff, Alberta, Canada, 29 September–3 October 2014, 174–178, 2014.
Heierli, J.: Solitary fracture waves in metastable snow stratifications, J. Geophys. Res., 110, F02008, https://doi.org/10.1029/2004JF000178, 2005.
Heierli, J.: Anticrack model for slab avalanche release, PhD, University of Karlsruhe, Karlsruhe, Germany, 102 pp., 2008.
Heierli, J., Gumbsch, P., and Zaiser, M.: Anticrack nucleation as triggering mechanism for snow slab avalanches, Science, 321, 240–243, https://doi.org/10.1126/science.1153948, 2008a.
Heierli, J., van Herwijnen, A., Gumbsch, P., and Zaiser, M.: Anticracks: A new theory of fracture initiation and fracture propagation in snow, Proceedings ISSW 2008, International Snow Science Workshop, Whistler, Canada, 21–27 September 2008, 9–15, 2008b.
Heierli, J., Gumbsch, P., and Sherman, D.: Anticrack-type fracture in brittle foam under compressive stress, Scripta Mater., 67, 96–99, https://doi.org/10.1016/j.scriptamat.2012.03.032, 2012.
Jamieson, J. B. and Johnston, C. D.: A fracture-arrest model for unconfined dry slab avalanches, Can. Geotech. J., 29, 61–66, https://doi.org/10.1139/t92-007, 1992.
Johnson, J. B.: A statistical micromechanical theory of cone penetration in granular materials, US Army Corps of Engineers, Engineer Research and Development Center, Hanover NH, USA, ERDC/CRREL Technical Report, ERDC/CRREL-TR-03-3, 32, 2003.
Löwe, H. and van Herwijnen, A.: A Poisson shot noise model for micro-penetration of snow, Cold Reg. Sci. Technol., 70, 62–70, https://doi.org/10.1016/j.coldregions.2011.09.001, 2012.
Marshall, H.-P. and Johnson, J. B.: Accurate inversion of high-resolution snow penetrometer signals for microstructural and micromechanical properties, J. Geophys. Res., 114, F04016, https://doi.org/10.1029/2009jf001269, 2009.
McClung, D. M.: Approximate estimates of fracture speeds for dry slab avalanches, Geophys. Res. Lett., 32, L08406, https://doi.org/10.1029/2005GL022391, 2005.
McClung, D. M. and Schaerer, P.: The Avalanche Handbook, 3rd ed., The Mountaineers Books, Seattle WA, USA, 342 pp., 2006.
Pudasaini, S. P. and Hutter, K.: Avalanche dynamics: Dynamics of rapid flows of dense granular avalanches, Springer, Berlin, Heidelberg, Germany, 602 pp., 2007.
Reuter, B. and Schweizer, J.: Describing snow instability by failure initiation, crack propagation, and slab tensile support, Geophys. Res. Lett., 45, 7019–7027, https://doi.org/10.1029/2018GL078069, 2018.
Reuter, B., Proksch, M., Löwe, H., van Herwijnen, A., and Schweizer, J.: On how to measure snow mechanical properties relevant to slab avalanche release, Proceedings ISSW 2013, International Snow Science Workshop, Grenoble, France, 7–11 October 2013, 7–11, 2013.
Reuter, B., Schweizer, J., and van Herwijnen, A.: A process-based approach to estimate point snow instability, The Cryosphere, 9, 837–847, https://doi.org/10.5194/tc-9-837-2015, 2015.
Reuter, B., Proksch, M., Löwe, H., van Herwijnen, A., and Schweizer, J.: Comparing measurements of snow mechanical properties relevant for slab avalanche release, J. Glaciol., 65, 55–67, https://doi.org/10.1017/jog.2018.93, 2019.
Rosendahl, P. L. and Weißgraeber, P.: Modeling snow slab avalanches caused by weak-layer failure – Part 1: Slabs on compliant and collapsible weak layers, The Cryosphere, 14, 115–130, https://doi.org/10.5194/tc-14-115-2020, 2020.
Schneebeli, M. and Johnson, J. B.: A constant-speed penetrometer for high-resolution snow stratigraphy, Ann. Glaciol., 26, 107–111, https://doi.org/10.3189/1998AoG26-1-107-111, 1998.
Schweizer, J., Jamieson, J. B., and Schneebeli, M.: Snow avalanche formation, Rev. Geophys., 41, 1016, https://doi.org/10.1029/2002RG000123, 2003.
Schweizer, J., van Herwijnen, A., and Reuter, B.: Measurements of weak layer fracture energy, Cold Reg. Sci. Technol., 69, 139–144, https://doi.org/10.1016/j.coldregions.2011.06.004, 2011.
Schweizer, J., Bartelt, P., and van Herwijnen, A.: Snow avalanches, in: Snow and Ice-Related Hazards, Risks, and Disasters, 2nd ed., edited by: Haeberli, W. and Whiteman, C., Elsevier, Amsterdam, the Netherlands, 377–416, 2021.
Sigrist, C. and Schweizer, J.: Critical energy release rates of weak snowpack layers determined in field experiments, Geophys. Res. Lett., 34, L03502, https://doi.org/10.1029/2006GL028576, 2007.
Sigrist, C., Schweizer, J., Schindler, H. J., and Dual, J.: On size and shape effects in snow fracture toughness measurements, Cold Reg. Sci. Technol., 43, 24–35, https://doi.org/10.1016/j.coldregions.2005.05.001, 2005.
Sigrist, C., Schweizer, J., Schindler, H. J., and Dual, J.: Measurement of fracture mechanical properties of snow and application to dry snow slab avalanche release, Geophysical Research Abstracts, 8, 08760, 2006.
Trottet, B., Simenhois, R., Bobillier, G., van Herwijnen, A., Jiang, C., and Gaume, J.: From sub-Rayleigh to intersonic crack propagation in snow slab avalanche release, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8253, https://doi.org/10.5194/egusphere-egu21-8253, 2021.
Turner, D. Z.: Digital Image Correlation Engine (DICe) Reference Manual, National Technology & Engineering Solutions of Sandia, Albuquerque, New Mexico, USA, SAND2015-10606 O, 2015.
van Herwijnen, A.: Experimental analysis of snow micropenetrometer (SMP) cone penetration in homogeneous snow layers, Can. Geotech. J., 50, 1044–1054, https://doi.org/10.1139/cgj-2012-0336, 2013.
van Herwijnen, A. and Birkeland, K. W.: Measurements of snow slab displacement in Extended Column Tests and comparison with Propagation Saw Tests, Cold Reg. Sci. Technol., 97, 97–103, https://doi.org/10.1016/j.coldregions.2013.07.002, 2014.
van Herwijnen, A. and Heierli, J.: In-situ measurement of the mechanical energy associated with crack growth in weak snowpack layers and determination of the fracture energy, Geophysical Research Abstracts, 12, 11743, 2010.
van Herwijnen, A. and Jamieson, B.: High-speed photography of fractures in weak snowpack layers, Cold Reg. Sci. Technol., 43, 71–82, https://doi.org/10.1016/j.coldregions.2005.05.005, 2005.
van Herwijnen, A., Schweizer, J., and Heierli, J.: Measurement of the deformation field associated with fracture propagation in weak snowpack layers, J. Geophys. Res., 115, F03042, https://doi.org/10.1029/2009JF001515, 2010.
van Herwijnen, A., Bair, E. H., Birkeland, K. W., Reuter, B., Simenhois, R., Jamieson, B., and Schweizer, J.: Measuring the mechanical properties of snow relevant for dry-snow slab avalanche release using particle tracking velocimetry, Proceedings ISSW 2016, International Snow Science Workshop, Breckenridge CO, USA, 3–7 October 2016, 397–404, 2016a.
van Herwijnen, A., Gaume, J., Bair, E. H., Reuter, B., Birkeland, K. W., and Schweizer, J.: Estimating the effective elastic modulus and specific fracture energy of snowpack layers from field experiments, J. Glaciol., 62, 997–1007, https://doi.org/10.1017/jog.2016.90, 2016b.
Walters, D. J. and Adams, E. E.: Quantifying anisotropy from experimental testing of radiation recrystallized snow layers, Cold Reg. Sci. Technol., 97, 72–80, https://doi.org/10.1016/j.coldregions.2013.09.014, 2014.
Short summary
The modern picture of the snow slab avalanche release process involves a
dynamic crack propagation phasein which a whole slope becomes detached. The present work contains the first field methodology which provides the temporal and spatial resolution necessary to study this phase. We demonstrate the versatile capabilities and accuracy of our method by revealing intricate dynamics and present how to determine relevant characteristics of crack propagation such as crack speed.
The modern picture of the snow slab avalanche release process involves a
dynamic crack...
