Using unsteady hydraulic analogs to model waves and short-lived peak velocities and peak impact loads associated with snow avalanche flow

Snow avalanches are geophysical phenomena that affect life and property. Of interest to researchers is the ability to determine velocities, impact pressures, and runout distances of avalanches. Of interest in this research was the incorporation of waves and surges into a hydraulic numerical model of avalanche flow that leads to short-lived peak velocities and impact pressures.; The one-dimensional, unsteady, gradually varying free-surface, open channel equations are solved numerically using the Lax Diffusive Scheme. The numerical model is applied to simulate avalanche flow and to capture the existence of waveforms leading to the estimation of short-lived peak velocities and impact pressures for any point along a given avalanche track.; The simulation of both laboratory and field experiments was presented to demonstrate the viability of the discretization scheme. In order to verify numerical results of this new numerical model, results from the Swiss hydraulic continuum model for avalanche motion (gradually varying hydraulic continuum flow) are presented and compared. The Lax Diffusive Scheme provides acceptable results when compared to these laboratory and full-scale avalanche results and when compared to the Swiss numerical results.; Numerous simulations are presented to demonstrate the ability for the numerical model to capture and track waveforms within the avalanche flow, to estimate short-lived peak velocities, and to impact pressures for any position along the avalanche track-especially when perturbations (i.e., terrain changes) are introduced into the flow. These perturbations are particularly evident when releasing a wave-like form from rest down an incline. However, difficulties are encountered when trying to simulate in-situ results. The Mount Baldy Avalanche simulations demonstrate the difficulties of imparting a lasting disturbance and re-creating the richness of the in-situ data.