Impulse water waves generated by snow avalanches

Mohamed Naaim (1)

1 UR ETGR (ETNA) - Erosion torrentielle neige et avalanches

Retaining dams devoted to artificial snow production, are most of the time located in the vicinity of steep slope areas and may be threatened by snow avalanche impacts. To assess the risk of over toppings (overflows), the estimation of the consequences of an avalanche impact in terms of wave magnitude is required. Due to the low density ratio between the snow and the water, the extrapolation of available scaling laws, established for high density ratios (landslides and debris flows), may lead to a misestimating of the wave characteristics. To extend the existing scaling laws in the low density ratio domain, multiphase numerical simulations are conducted. The objective is to investigate the nature and the magnitude of the water wave generated by the impact of a natural fluid of low density. Both vertical and horizontal impacts are considered and their effects are studied. The dependence of the wave amplitude on the density ratio is highlighted. The main conclusions drawn up from this study are the following. The wave amplitude is an exponential function of the avalanche density. This function is very steep for low density ratios. For density ratios higher than 0.5, the trend is much smooth and tends towards the scaling laws established for landslides.

Mots clés: AVALANCHE; VAGUE; LAC; EVALUATION DES RISQUES; IMPULSE WATER WAVE; SNOW AVALANCHE; MOUNTAIN LAKE

Domaines: Sciences de l'environnement

Mohamed Naaim. Impulse water waves generated by snow avalanches. International Snow Science Workshop (ISSW), Oct 2013, Grenoble – Chamonix Mont-Blanc, France. p. 619 - p. 624. ⟨hal-00951695⟩