Hierarchy theory as a conceptual framework for scale issues in avalanche forecast modeling

Abstract

Although scale issues have been defined to be one of the most crucial topics in geosciences, they have received only limited attention in avalanche research. A thorough understanding of these issues in avalanche forecasting, however, is fundamental for the development of useful prediction models. After the definition of relevant terms, the different aspects of scale issues are introduced in detail. We present hierarchy theory (Ahl and Allen, 1996) as a potential framework for the multi-scale characteristics of the avalanche phenomenon. We suggest a temporal hierarchy, where the main contributing factors are ordered into seven levels according to their temporal-scale characteristics with respect to avalanche forecasting. Within each level there are individual spatial hierarchies, which result in a two-dimensional structure. This process-oriented framework is compared to the data classification scheme of LaChapelle (1980), which is based on informational entropy. Scale issues in prediction modeling and the consequences of the new framework for modeling efforts are discussed in detail. © International Glaciological Society.