Skip to main content
×
×
Home

Dispersive pressure and density variations in snow avalanches

  • Othmar Buser (a1) and Perry Bartelt (a1)
Abstract

Snow avalanches possess two types of kinetic energy: the kinetic energy associated with the mean velocity in the downhill direction and the kinetic energy associated with individual particle velocities that vary from the mean. The mean kinetic energy is directional; the kinetic energy associated with the velocity fluctuations is non-directional in the sense that it is connected to random particle movements. However, the rigid, basal boundary directs the random fluctuation energy into the avalanche. Thus, the random energy flux is converted to free mechanical energy which lifts and dilates the avalanche flow mass, changing the flow density and increasing the normal (dispersive) pressure and, as a consequence, changing the flow resistance. In this paper we derive macroscopic relations that link the production of the random kinetic energy to the perpendicular acceleration of the avalanche’s center of mass. We show that a single burst of fluctuation energy will produce pressures that oscillate around the hydrostatic pressure. Because we do not include a damping process, the oscillations of the center of mass remain, even if the production of random kinetic energy stops. We formulate relationships that can be used within the framework of depth-averaged mass and momentum equations that are often used to simulate snow avalanches in realistic terrain.

  • View HTML
    • Send article to Kindle

      To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      Dispersive pressure and density variations in snow avalanches
      Available formats
      ×
      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      Dispersive pressure and density variations in snow avalanches
      Available formats
      ×
      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      Dispersive pressure and density variations in snow avalanches
      Available formats
      ×
Copyright
References
Hide All
Bagnold, R.A. 1954. Experiments on a gravity-free dispersion of large solid spheres in a Newtonian fluid under shear. Proc. R. Soc. London, Ser. A, 225(1160), 4963.
Bartelt, P. and Buser, O.. 2011. Dispersive pressure and velocity fluctuations in avalanches. Reply to comment by K. Kelfoun and T. Davies on ‘A random kinetic energy model for rock avalanches: eight case studies’. J. Geophys. Res., 116(F1), F01015. (10.1029/2010JF001956.)
Bartelt, P. and McArdell, B.W.. 2009. Granulometric investigations of snow avalanches. J. Glaciol., 55(193), 829833.
Bartelt, P., Buser, O. and Platzer, K.. 2006. Fluctuation–dissipation relations for granular snow avalanches. J. Glaciol., 52(179), 631643.
Bartelt, P., Buser, O. and Platzer, K.. 2007. Starving avalanches: frictional mechanisms at the tails of finite-sized mass movements. Geophys. Res. Lett., 34(20), L20407. (10.1029/2007GL031352.)
Boyce, W.E. and DiPrima, R.C.. 1977. Elementary differential equations and boundary value problems. New York, Wiley.
Buser, O. and Bartelt, P.. 2009. Production and decay of random kinetic energy in granular snow avalanches. J. Glaciol., 55(189), 312.
Christen, M., Kowalski, J. and Bartelt, P.. 2010. RAMMS: numerical simulation of dense snow avalanches in three-dimensional terrain. Cold Reg. Sci. Technol., 63(1–2), 114.
Gauer, P. and 7 others. 2007a. On full-scale avalanche measurements at the Ryggfonn test site, Norway. Cold Reg. Sci. Technol., 49(1), 3953.
Gauer, P., Kern, M., Kristensen, K., Lied, K., Rammer, L. and Schreiber, H.. 2007b. On pulsed Doppler radar measurements of avalanches and their implication to avalanche dynamics. Cold Reg. Sci. Technol., 50(1–3), 5571.
Gubler, H. 1987. Measurements and modelling of snow avalanche speeds. IAHS Publ. 162 (Symposium at Davos 1986 –Avalanche Formation, Movement and Effects), 405420.
Issler, D. and Gauer, P.. 2008. Exploring the significance of the fluidized flow regime for avalanche hazard mapping. Ann. Glaciol., 49, 193198.
Kern, M., Bartelt, P., Sovilla, B. and Buser, O.. 2009. Measured shear rates in large dry and wet snow avalanches. J. Glaciol., 55(190), 327338.
Naaim, M., Naaim-Bouvet, F., Faug, T. and Bouchet, A.. 2004. Dense snow avalanche modeling: flow, erosion, deposition and obstacle effects. Cold Reg. Sci. Technol., 39(2–3), 193204.
Norem, H., Irgens, F. and Schieldrop, B.. 1987. A continuum model for calculating snow avalanche velocities. IAHS Publ. 162 (Symposium at Davos 1986 – Avalanche Formation, Movement and Effects), 363379.
Platzer, K., Bartelt, P. and Kern, M.. 2007. Measurements of dense snow avalanche basal shear to normal stress ratios (S/N). Geophys. Res. Lett., 34(7), L07501. (10.1029/2006GL028670.)
Salm, B. 1993. Flow, flow transition and runout distances of flowing avalanches. Ann. Glaciol., 18, 221226.
Savage, S.B. and Hutter, K.. 1989. The motion of a finite mass of granular material down a rough incline. J. Fluid Mech., 199, 177215.
Savage, S.B. and Hutter, K.. 1991. The dynamics of avalanches of granular materials from initiation to runout. Part I: analysis. Acta Mech., 86(1–4), 201223.
Schaefer, M., Bugnion, L., Kern, M. and Bartelt, P.. 2010. Position dependent velocity profiles in granular avalanches. Granular Matter, 12(3), 327336.
Turnbull, B. and McElwaine, J.N.. 2007. A comparison of powder-snow avalanches at Vallée de la Sionne, Switzerland, with plume theories. J. Glaciol., 53(180), 3040.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Glaciology
  • ISSN: 0022-1430
  • EISSN: 1727-5652
  • URL: /core/journals/journal-of-glaciology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Metrics

Full text views

Total number of HTML views: 3
Total number of PDF views: 33 *
Loading metrics...

Abstract views

Total abstract views: 38 *
Loading metrics...

* Views captured on Cambridge Core between 8th September 2017 - 22nd June 2018. This data will be updated every 24 hours.