Modified avalanche risk equations to account for waiting traffic on avalanche prone roads

摘要

Avalanche risk evaluation has historically been calculated using two main methods, the Avalanche Hazard Index (AHI) and a Probability of Death for Individuals (PDI) method. While the AHI method considers the risk posed to moving and waiting traffic, recently developed equations for PDI do not account for the waiting traffic component despite the recognition that the waiting traffic is extremely significant in terms of the total risk. A simple method of incorporating the risk posed to waiting traffic in a modified PDI equation is suggested and applied to the Milford Road in south west New Zealand. The new equations for PDI raise individual and collective risk on a theoretically uncontrolled road significantly though comparisons of calculated risks and actual avalanche encounters for other areas suggest that these risks may be overestimated.