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Changes in the shear strength and micro-penetration hardness of a buried surface-hoar layer

  • Karl W. Birkeland (a1) (a2), Kalle Kronholm (a3), Martin Schneebeli (a3) and Christine Pielmeier (a3)

Abstract

We investigated a buried surface-hoar layer using the SnowMicroPen (SMP), an instrument designed to measure detailed snowpack profiles.We collected data from two adjacent parts of a slope 6 days apart. In addition, one manual snowpack profile was sampled each day, as well as 50 quantified loaded column tests (QLCTs) which provided an index of shear strength. For the SMP data, a 900 m2 area was sampled on both days in a grid with points 3 mapart, with some sub-areas of more closely spaced measurements. We collected 86 SMP profiles on the first day and 129 on the second day. Our analyses involved manually locating layer boundaries and calculating statistics for the force signal through the surface-hoar layer. The shear strength index increased by 40% between the two sampling days, but the SMP data show no statistical difference in layer thickness, and the mean, minimum, median, and a variety of percentile measures of the SMP force signal through the layer also do not change. Interestingly, the maximum hardness, and the variance and coefficient of variation of the SMP signal, increased. Since the small SMP tip might only break one or a couple of bonds as it passes through the weak layer, we interpret these changes as being indicative of increasing bond strength. Though we cannot specifically tie the increasing maximum hardness of the SMP signal to our QLCT results, our work suggests that the maximum SMP signal within buried surface-hoar layers may be useful for tracking increases in the shear strength of those layers.

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References

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Birkeland, K.W. and Landry, C. C.. 2002. Changes in spatial patterns of snow stability through time. In Stevens, J.R., ed. International Snow ScienceWorkshop 2002, 29 September–4 October 2002, Pentiction, British Columbia. Proceedings. Victoria, B.C., B.C. Ministry of Transportation. Snow Avalanche Programs, 482–490. (http://www.fsavalanche.org/NAC/techPages/articles/02_ISSWspatial__var__time.pdf.)
Chalmers, T. S. and Jamieson, J. B.. 2001. Extrapolating the skier stability of buried surface-hoar layers from study plot measurements. Cold Reg. Sci. Technol., 33(2–3), 163–177.
Chalmers, T. S. and Jamieson, J. B.. 2003. A snow-profile-based forecasting model for skier-triggered avalanches on surface-hoar layers in the Columbia Mountains of Canada. Cold Reg. Sci. Technol., 37(3), 373–389.
Colbeck, S.C. and 7 others. 1990. The international classification for seasonal snow on the ground. Wallingford, Oxfordshire, International Association of Scientific Hydrology. International Commission on Snow and Ice.
Davis, R. E., Jamieson, B., Hughes, J. and Johnston, C.. 1997 .Observations on buried surface hoar−persistent failure planes for slab avalanches in British Columbia, Canada. In ISSW’96. International Snow Science Workshop, 6–10 October 1996, Banff, Alberta. Proceedings. Revelstoke, B.C., Canadian Avalanche Association, 81–85.
Davis, R. E., Jamieson, B. and Johnston, C. D.. 1998. Observations on buried surface hoar in British Columbia, Canada−section plane analysis of layer evolution. In ISSW’98. International Snow Science Workshop, 27 September–1 October 1998, Sunriver, Oregon. Proceedings. Seattle, WA, Washington State Department of Transportation, 86–92.
Hachikubo, A. and Akitaya, E.. 1997. Effect of wind on surface-hoar growth on snow. J. Geophys. Res., 102(D4), 4367–4373.
Jamieson, J. B. 1995. Avalanche prediction for persistent snow slabs. (Ph.D. thesis, University of Calgary.)
Jamieson, J. B. and Johnston, C.D.. 1999. Snowpack factors associated with strength changes of buried surface-hoar layers. Cold Reg. Sci. Technol., 30(1–3), 19–34.
Jamieson, J. B. and Schweizer, J.. 2000. Texture and strength changes of buried surface-hoar layers with implications for dry snow-slab avalanche release. J. Glaciol., 46(152), 151–160.
Johnson, J. B. and Schneebeli, M.. 1999. Characterizing the microstructural and micromechanical properties of snow. Cold Reg. Sci.Technol., 30(1–3), 91–100.
Landry, C.C. 2002. Spatial variation in snow stability on uniform slopes: implications for extrapolation to surrounding terrain. (M.Sc. thesis, Montana State University.) (http://www.fsavalanche.org/NAC/techPages/theses/landry.pdf.)
Landry, C.C., Borkowski, J. and Brown, R. L.. 2001. Quantified loaded column stability test: mechanics, procedure, sample-size selection, and trials. Cold Reg. Sci. Technol., 33(2–3), 103–121.
Landry, C.C., Birkeland, K. W., Hansen, K., Borkowski, J., Brown, R. L. and Aspinall, R.. 2002. Snow stability on uniform slopes: implications for avalanche forecasting. In Stevens, J.R., ed. International Snow Science Workshop 2002, 29 September–4October 2002, Pentiction, British Columbia. Proceedings. Victoria, B.C., B.C. Ministry of Transportation. Snow Avalanche Programs, 532–539. (http://www.fsavalanche.org/NAC/techPages/articles/02_ISSW-Landry.pdf.)
Lang, R. M., Leo, B. R. and Brown, R. L.. 1984. Observations on the growth process and strength characteristics of surface hoar. In ISSW’84. A merging of theory and practice. International Snow Science Workshop, 24–27 October 1984, Aspen, Colorado. Proceedings. Aspen, CO, ISSW Workshop Committee, 188–195.
Pielmeier, C. and Schneebeli, M.. In press. Snow stratigraphy measured by snow hardness and compared to surface section images. Cold Reg. Sci. Technol.
Pielmeier, C., Schneebeli, M. and Stucki, T.. 2001. Snow texture: a comparison of empirical versus simulated texture index for Alpine snow. Ann. Glaciol., 32, 7–13.
Research Systems Inc. (RSI). 1998. IDL reference guides. Vols. I and II. Boulder, CO, Research Systems Inc.
Schneebeli, M. 1999. High resolution penetrometry in the high-porosity material snow. In International Workshop on Penetrometry in the Solar System. Proceedings. Vienna, Verlag der Österreichischen Akademie der WissenschaftenWien, 61–72.
Schneebeli, M., Pielmeier, C. and Johnson, J. B.. 1999. Measuring snow microstructure and hardness using a high resolution penetrometer. Cold Reg. Sci. Technol., 30(1–3), 101–114.
Statsoft. 1994. Statistica Volume I: general conventions and statistics I. Tulsa, OK, Statsoft.

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