Remote analysis of avalanche terrain features: identifying routes, avoiding hazards

The threat of avalanches to winter recreationalists and mountain communities is well known. Geographic Information Systems (GIS) technology has been used to augment avalanche forecast and control programs in many parts of the United States and Europe. Successful GIS approaches combine terrain modeling, historical avalanche data and avalanche flow modeling to identify and predict avalanche probability and intensity for relatively small geographic areas (e.g., highway corridors, commercial ski areas and municipalities) (McCollister & Birkeland, 2006). However, little research has focused on the vast backcountry areas between such small, populated areas. With the advent of lighter, better equipment for both backcountry skiers and snowmobilers, recreationalists increasingly visit these areas and are at risk from avalanches. Thus, an effort to reevaluate and improve avalanche risk information available to winter recreationalists is warranted. This study developed and evaluated geoprocessing methods using readily available and inexpensive spatial data to identify two terrain features of particular importance in evaluating avalanche risk, depositional terrain traps and trigger points. Forest density layers for display and geoprocessing purposes were also created from several data sources. Avalanche terrain hazards were identified from slope curvature models where areas of aspect change were filtered out along with moderate and heavy forest and low angle slope areas. Field trials confirmed that such methods could improve decision making and route finding in winter backcountry areas.