The effect of slab touchdown on anticrack arrest in propagation saw tests

Abstract. Understanding crack phenomena in the snowpack and their role in avalanche formation is imperative for hazard prediction and mitigation. Many studies have explored how structural properties of snow contribute to the initial instability of the snowpack, focusing particularly on failure initiation within weak snow layers and the onset of crack propagation. This work addresses the subsequent stage, the effect of slab touchdown after weak layer failure in mixed-mode loading (compresive anticrack (mode I) and shear (mode II) loading). Here we show that slab touchdown reduces the energy release rate, potentially leading to crack arrest, even in static considerations. This finding challenges the notion that dynamic properties of snow layers and spatial snowpack changes alone dictate arrest, highlighting the critical role of mechanical interactions between the slab, weak layer, and base layer. By integrating these findings into the broader context of snowpack stability analysis, we contribute to a more nuanced understanding of avalanche initiation mechanisms. By offering a comprehensive model that can be applied in diverse geophysical settings (https://github.com/2phi/weac), this work extends the scope of avalanche science, promising new strategies for hazard assessment and mitigation.