Rockfalls on snow-covered scree. Contribution to the study of a mechanism
DOI:
https://doi.org/10.26485/BP/1994/33/3Keywords:
rockfall, snow covered talus slopes, fall storting, protalus-rampartAbstract
French-language publication.
Original title: Les chutes de pierres sur les eboulis recouverts de neige. Contribution a l'etude d'un mecanisme
In snow environments, rockfall generally occurs on snow covered talus slopes. But, movement of individual stones on snow talus has not been really studied. Yet, one generally considers this mechanism to have an important role in the morphology of talus slopes in cold environments especially in the formation of protalus rampart. We conducted experiments to isolate the parameters which control the path of particles and their orientation at rest: impact resistance of snow cover, roughness of the surface, size and morphology of particles, nature of the impact appear to be more important. Movement of these particles is not as simple as was originally thought: sliding and rolling occur in various proportions during the moving and the increasing resistance of snow throughout the spring does not allow the blocks to concentrate in a confined area at the toe of the slope. These arguments allow one to question the classical model of the protalus-rampart formation. We bring new suggestions about the origin of these forms.
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