Speaker
Description
Climate change is significantly affecting mountain environments, with increasing temperatures altering snowpack stability and potentially increasing the frequency of snow-slab avalanches. Understanding how temperature influences avalanche triggering is therefore crucial for assessing the impact of warming climates on snow hazards. Although field observations consistently indicate that temperature plays a key role in avalanche release, a rigorous analytical framework capable of quantitatively describing this influence is still lacking.
In this work, we develop a theoretical framework to investigate the thermo-mechanical mechanisms governing avalanche triggering. The model builds upon recent papers in which the classical Griffith energy balance for fracture has been extended to account for coupled thermo-mechanical loading conditions. While those studies primarily addressed Mode I fracture, here we focus on Mode II (shear) fracture, which more accurately represents the failure of the weak snow layer responsible for slab detachment.
The formulation explicitly incorporates finite slab dimensions and friction. Starting from an ab-initio discrete description, the model consistently recovers classical continuum fracture mechanics results in the appropriate limiting case. Interestingly, applying the Quantized Fracture Mechanics framework to the continuum formulation leads back to the discrete model, highlighting the interplay between discrete and continuum descriptions in fracture processes.
Within this energetic perspective, snowpack stability emerges from the nonlinear competition between elastic deformation energy, external loading, fracture energy, frictional dissipation, and entropic contributions associated with thermal fluctuations. Avalanche release can therefore be interpreted as a thermo-mechanical instability arising from thermo-mechanical interactions within the snowpack.
The analysis predicts a temperature-dependent critical load for weak-layer failure that decreases with increasing temperature according to the scaling law $(1-T/T_c)^{1/2}$, where the critical temperature $T_c$ depends on the system’s parameters.
These results provide a quantitative framework linking temperature variations to snowpack stability and establish a direct theoretical connection between climate warming and the increased likelihood of avalanche triggering.