An ArcGIS Model for Avalanche Risk Assessment in the North Cascades, Washington

Abstract

ABSTRACTReports of avalanche-related deaths have increased over the last fifty years in the United States. Although incidents occurring in Washington State and in the North Cascades do not reflect the bulk of avalanche-related casualties in the United States, it remains an annual concern for both recreational safety and transportation. This research seeks to apply and update methods from previous studies to evaluate avalanche risk in the North Cascades. Hazardous areas are identified by naturally occurring avalanche trigger zones. This study involves a mixed-method analysis using predefined geomorphic conditions, such as constant slope and sudden slope change, as well vegetation density, to identify natural avalanche trigger zones using ArcGIS. The outcome of the hazard assessment model is then evaluated using coordinates for reported avalanche debris sites and imagery interpretation. The postprocess evaluation also uses onsite ground photos of avalanche debris, captured by skiers, that help further assess how accurately the geographic information systems process is able to depict high-risk avalanche zones. A non-region-specific tool was produced in the form of an ArcGIS model that can be used to evaluate the avalanche hazard criteria in any regional area of interest.