Title Wind and drifting-snow gust factor in an alpine context
Author Naaim-Bouvet, F.; Naaim, M.; Bellot, H.; Nishimura, K.
Author Affil Naaim-Bouvet, F., Cemagref, Saint-Martin-d'Heres, France. Other: Nagoya University, Japan
Source Annals of Glaciology, 52(58), p.223- 230, . Publisher: International Glaciological Society, Cambridge, United Kingdom. ISSN: 0260-3055
Publication Date 2011
Notes In English. 26 refs. GeoRef Acc. No: 310188
Index Terms Alpine landscapes; avalanches; experimentation; mass movements (geology); forecasting; simulation; environment simulation; snow; statistical analysis; velocity; wind tunnels; wind velocity; France- -French Alps; alpine environment; Alps; Europe; experimental studies; France; French Alps; gust factor; Lac Blanc Pass; mass movements; natural hazards; numerical models; patterns; physical models; prediction; probability; snowdrift; terrestrial environment; transport; Western Europe; wind transport; winds
Abstract Wind-transported snow is a common phenomenon in cold windy areas, creating snowdrifts and contributing significantly to the loading of avalanche release areas. It is therefore necessary to take into account snowdrift formation both in terms of predicting and controlling drift patterns. Particularly in an Alpine context, drifting snow is a nonstationary phenomenon, which has not been taken into account in physical modeling carried out in wind tunnels or in numerical simulations. Only a few studies have been conducted to address the relation between wind gusts and drifting-snow gusts. Consequently, the present study was conducted at the Lac Blanc pass (2700 ma.s.l.) experimental site in the French Alps using a snow particle counter and a cup anemometer in order to investigate drifting-snow gusts. First, it was shown that the behavior of the wind gust factor was coherent with previous studies. Then the definition of wind gust factor was extended to a drifting-snow gust factor. Sporadic drifting-snow events were removed from the analysis to avoid artificially high drifting-snow gust factors. Two trends were identified: (1) A high 1 s peak and a mean 10 min drifting-snow gust factor, greater than expected, were observed for events that exhibited a gamma distribution on the particle width histogram. The values of drifting-snow gust factors decreased with increasing gust duration. (2) Small drifting-snow gusts (i.e. smaller than or of the same order of magnitude as wind gusts) were also observed. However, in this case, they were systematically characterized by a snow particle size distribution that differed from the two-parameter gamma probability density function.
Publication Type journal article
Record ID 65007375