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Abstract

Avalanches are one of the major natural hazards of the cryosphere, strongly threatening the safety of people's lives, infrastructure, ecology and transport tourism in the highland mountains. In recent years, with the climate change intensifies, avalanche hazards, especially the dry snow slab avalanche are increasing rapidly all over the world. Therefore, it is urgent to investigate the mechanism of avalanche hazards and to establish an avalanche warning system. We have performed numerical simulations by the discrete element method to investigate the formation mechanism of slab avalanche. The results indicate avalanche formation as a mixed-mode fracture process. During the initial formation, the cracks propagate slowly along the weak layer and after reaching a critical length, the cracks propagate rapidly, the volume of the weak layer collapses and the slab layer appears to settling. Finally, when the cracks propagate to a certain distance, the slab layer fractures and the avalanche begins to release. The failure process of the weak layer is affected by variety factors such as the properties of the snowpack and the topography. Our results also provide a good explanation of the avalanche formation and compose a foundation for avalanche hazard warning and protection.