Using Geographic Information Systems for Avalanche Work

McCollister, C., & Birkeland, K. (2006). Using Geographic Information Systems for Avalanche Work. The Avalanche Review, 24(4).

This article presents relatively early work with GIS and avalanche mapping. The researcher objective was to determine if the use of GI systems are appropriate for mapping avalanche start zones/paths and for avalanche forecasting, which are arguably the two most widespread uses of GIS in the ski industry.

According to McCollister and Birkeland, the primary layers for mapping avalanche paths with a GI system are the vegetation and digital elevation model (DEM) layers. They acknowledge these layers are only useful if they are accurate and up-to-date, reflecting the current state of the terrain. Landslides, logging, forest fires, and tree growth can can significantly alter a landscape in a short period of time, which in turn affects the accuracy of any GI system's modeling of potential avalanche danger. Another aspect of great importance in the mapping of avalanche paths is the resolution of the DEM. Even a 3-meter resolution, they posit, can have large differences between what the layer displays and what is actually seen on the ground.

To determine the effectiveness and accuracy of GI systems at identifying avalanche start zones, this study compared the GIS results with historical avalanche data from Jackson Hole Mountain Resort. The GI system correctly identified 75% of avalanche start zones within the resort, but the software also identified an "enormous" amount of areas that were not. In fact, for every correct avalanche start zone identified, it identified 10 false positives. The authors attribute this to the fact that the slope angle layers did not provide enough information to make accurate predictions. This relates back to the importance of high-resolution DEMs for providing accurate topography.

The other important role of GIS in the ski industry is building avalanche forecasting models and avalanche forecasting products. This is a far more difficult task than mapping avalanche paths, the authors note, because there are so many factors that go into assessing snow stability. Inputting weather data, even from resort and telemetry weather stations, is insufficient because of fine scale weather differences in alpine terrain.

This research is of importance to me because it documents early work within the field of avalanche hazard mapping. It gives me a baseline from which to understand how the technology and techniques have evolved in the last 20 years.