23 Mar 2022
23 Mar 2022
Status: a revised version of this preprint is currently under review for the journal TC.

Environmental Conditions for Snow Cornice Formation tested in a Wind Tunnel

Hongxiang Yu1,3,4, Guang Li1,2,3,4, Benjamin Walter4, Michael Lehning3,4, Jie Zhang1, and Ning Huang1 Hongxiang Yu et al.
  • 1College of Civil engineering and Mechanics, Lanzhou University, Lanzhou, 730000, China
  • 2College of Atmospheric Science, Lanzhou University, Lanzhou, 730000, China
  • 3College of Architecture Civil and Environmental Engineering, Ecole Polytechnique Federal de Lausanne, Lausanne, 1015, Switzerland
  • 4WSL Institute for Snow and Avalanche Research SLF, Davos, 7260, Switzerland

Abstract. Snow cornices growing on the lee of mountain ridges are a common feature in alpine and polar regions during snow seasons. They can result in potential avalanche risk when they crack and fall. Current studies of cornices mainly focus on their deformation, collapsing, and avalanche risk via field observations. Few studies have paid attention to the accretion process of cornices, especially on their horizontal growth which enhances the instability of cornices. In this work, experiments in a cold laboratory under various wind conditions are carried out to investigate the environmental conditions and the internal physical mechanism of cornice formation. The results show that – for the specific settings in our wind tunnel – cornices appear only under moderate wind speeds which lead to necessary net mass flux divergence near the edge. The fastest growth rate is with winds approximately 40 % higher than the rebound threshold wind speed for snow transport because then the snow mass supply to the cornice edge is sufficient. Mass collection efficiency on the cornice surface decreases with the increasing wind speed. This work improves our understanding of cornice formation.

Hongxiang Yu et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on tc-2022-27', Anonymous Referee #1, 21 Apr 2022
  • RC2: 'Comment on tc-2022-27', Holt Hancock, 04 May 2022

Hongxiang Yu et al.

Hongxiang Yu et al.


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Short summary
Snow cornices lead to potential risk in causing snow avalanche hazards, which are still unknown so far. We carried out a wind tunnel experiment in a cold lab to investigate the environmental conditions for snow cornice accretion recorded by a camera. Results show that cornices appear only under moderate wind speeds, which leads to necessary mass flux divergence near the edge. These results improve our understanding of cornice formation and have implications for predicting snow hazards.