PhD Seminar • Natural Phenomena Simulation • An Assessment of Light Penetration into Snow with Implications Leading to the Prediction of Avalanche Conditions

Tuesday, September 28, 2021 3:00 pm - 3:00 pm EDT (GMT -04:00)

Please note: This PhD seminar will be given online.

Petri Varsa, PhD candidate
David R. Cheriton School of Computer Science

Supervisor: Professor Gladimir Baranoski

Snow avalanches are a natural hazard that incur great cost to both property and to human welfare. Slab avalanches occur when a cohesive slab of snow is released over an extended plane of weakness. This happens when a stress is introduced to a slab layer which has formed on top of a weak layer. The formation of the weak layer that governs slab releases is difficult to predict, making this category of avalanche hazardous. The plane of the weak layer may be formed of faceted crystals either at the surface or at a subsurface depth through morphological processes involving the transport of heat and vapour pressure gradients through the snowpack. Elucidating the formation of subsurface faceted crystals will advance the current understanding about the formation of snow slabs, which in turn, could be used in the prediction of slope failure. The formation process of subsurface faceted crystals is tied to the penetration of solar radiation into the snowpack. More specifically, absorbed radiation provides the energy that gives rise to the morphological processes governing crystal growth. Consequently, the quantification of light penetration through snow is of interest for studies on the formation of the weak layers associated with snow failure.

Despite its importance, investigations of light penetration through snow are still scarce in the literature, and the datasets obtained from field work are affected by experimental limitations. To overcome these limitations and to advance the understanding of light penetration into near-surface layers of snow, we employed a predictive in silico experimental setup. Our findings demonstrate that snow grain size and sample density must be carefully accounted for when estimating the quantity of solar radiation contributing to the subsurface morphological processes that form faceted crystals. In addition, our in silico experiments provide a detailed assessment of the hyperspectral transmission profiles at different depths.

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