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Failure of a layer of buried surface hoar
Author(s) -
Reiweger Ingrid,
Schweizer Jürg
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl045433
Subject(s) - snowpack , snow , shear (geology) , slab , materials science , geology , deformation (meteorology) , particle image velocimetry , anisotropy , layer (electronics) , composite material , surface layer , shear stress , geotechnical engineering , optics , mechanics , geomorphology , geophysics , physics , turbulence
In order to study the formation of the initial failure leading to dry‐snow slab avalanche release, we performed loading experiments in a cold laboratory with natural samples including a layer of buried surface hoar. The experimental setup was such that the layered snow samples were loaded continuously for various tilt (slope) angles; loading rates varied between 1 and 20 Pa s −1 . The stress at fracture decreased with increasing loading rate and increasing slope angle, i.e., increasing shear component of the load. The latter result means that the layer was stronger in compression than in shear which is attributed to the particularly anisotropic nature of layers of buried surface hoar. Particle image velocimetry revealed that almost 90% of the sample's global deformation was concentrated in the weak layer. For avalanche release our results imply that the shear component of deformation is of particular importance for failure initiation.