A conceptual model of avalanche hazard

Abstract

This conceptual model of avalanche hazard identifies the key components of avalanche hazard and structures them into a systematic, consistent workflow for hazard and risk assessments. The method is applicable to all types of avalanche forecasting operations, and the underlying principles can be applied at any scale in space or time. The concept of an avalanche problem is introduced, describing how different types of avalanche problems directly influence the assessment and management of the risk. Four sequential questions are shown to structure the assessment of avalanche hazard, namely: (1) What type of avalanche problem(s) exists? (2) Where are these problems located in the terrain? (3) How likely is it that an avalanche will occur? and (4) How big will the avalanche be? Our objective was to develop an underpinning for qualitative hazard and risk assessments and address this knowledge gap in the avalanche forecasting literature. We used judgmental decomposition to elicit the avalanche forecasting process from forecasters and then described it within a risk-based framework that is consistent with other natural hazards disciplines.

Characterizing the nature and variability of avalanche hazard in western Canada

“…The core information presented in Canadian avalanche bulletins consists of a characterization of the existing avalanche problems in uncontrolled backcountry areas according to the CMAH and predicted avalanched danger ratings for three elevation bands (alpine, treeline and below treeline) according to the five-point North American avalanche danger scale (Statham et al, 2010) for up to 3 days into the future. Also included in the bulletin record (but hidden from public users) are nowcast danger ratings that describe the severity of hazard in the three elevation bands at the time when the assessment was produced.…”

“…While researchers and practitioners have an experience-based understanding of the avalanche hazard associated with the three climate types, no studies have described the hazard character of an avalanche climate in detail. Since the 2009/2010 winter, the consistent use of Statham et al (2017) conceptual model of avalanche hazard in public avalanche bulletins in Canada has created a new quantitative record of avalanche hazard that offers novel opportunities for addressing this knowledge gap. We identified typical daily avalanche hazard situations using selforganizing maps (SOMs) and then calculated seasonal prevalence values of these situations.…”

Characterizing the nature and variability of avalanche hazard in western Canada

“…Our SOM analysis revealed twelve typical hazard situations that are combinations of the eight avalanche problem types 10 identified in the CMAH (Statham et al, 2017) …”

“…The CMAH including the concept of avalanche problems resonated well with Canadian avalanche professionals and the approach was quickly adopted into operational hazard assessment practices, information 15 systems and training programs (Statham et al, 2017).…”

“…In 2008, a group of Canadian and American avalanche forecasters and researchers developed a conceptual model of avalanche hazard (CMAH) to describe the judgmental avalanche hazard assessment process (Statham et al, 2017). The CMAH identifies 25 key components of avalanche hazard and structures them in a systematic workflow to provide a meaningful pathway for synthesizing available avalanche safety observations (weather, snowpack and avalanche observations), conceptualizing hazard conditions, and choosing appropriate risk treatment actions.…”