Effect of Snow Cornice Formation on Wind Fields and Snow Deposition: Insights From Numerical Simulations

Previous studies on small-scale snow cornices relied on wind-tunnel experiments to explore the suitable conditions for cornice growth. However, the absence of direct measurements of fluid and snow particle motions has limited the understanding of the mechanisms underlying snow cornice development. Here, we carried out numerical simulations under conditions identical to those of the wind-tunnel experiments. Wind profiles, snow deposition/erosion rates, surface friction velocity, and particle collision rates before and after cornice formation are quantitatively analyzed. The formation of snow cornices is primarily influenced by the shear stress on the surface, which is crucial for determining their development, while the net deposition rate on the edge plays a significant role in influencing the growth rate of these cornices. Furthermore, the analysis demonstrates that the presence of snow cornices enhances the likelihood of airborne snow particles adhering to the windward side of the edges, promoting downstream development. The growth of the snow cornice is predominantly influenced by the adhesion of settling particles at the edge, with only a small fraction of snow particles captured on the leeward side due to the effects of the return vortex (wake region). As snow cornices grow, the wind speed at the edge gradually decreases. While the collision rate of particles with the edge increases, further facilitating cornice growth. These insights contribute to a deeper understanding of snow cornice dynamics and their implications for snow stability in mountainous regions.