The Conceptual Model of Avalanche Hazard (CMAH) is a framework for evaluating avalanche hazard developed in a 2012 project by Parks Canada and the Canadian Avalanche Centre. The model was further refined between 2012 and 2017 by a team of international collaborators and published in 2018. It contains a narrative describing the framework and how to use it. The CMAH fits into the Operational Risk Assessment component of the Snow Avalanche Risk Management Framework.
Snow Avalanche Risk Management Framework. Adapted from Technical Aspects of Snow Avalanche Risk Management─Resources and Guidelines for Avalanche Practitioners in Canada (C. Campbell, S. Conger, B. Gould, P. Haegeli, B.Jamieson, & G. Statham Eds.). Revelstoke, BC, Canada: Canadian Avalanche Association 2016.
Avalanche forecasting is a complex process that requires the forecaster to synthesize a variety of data and evidence into a subjective assessment of the hazard. The process is highly influenced by human factors, personal experience, intuition, and intimate knowledge of the terrain, snowpack and weather patterns in the forecast area. By its nature, forecasting is greatly dependent on the individual forecaster. The CMAH endeavors to create a common framework and vocabulary for forecasters to use when assessing the hazard. The framework directly supports use with the North American Danger Scale, but is designed to be applied to all forecasting operations and to form a universally accepted standard basis for avalanche risk management decisions. The model itself, CMAH, consists of this basic framework for identifying, analyzing, and evaluating avalanche hazard as part of the risk management process.
Avalanche Problem Graphic. Adapted from Conceptual Model of Avalanche Hazard, 2017 By: Statham, Haegeli, Greene, Birkeland, Israelson, Tremper, Stethem, McMahon, White, Kelly.
The model can be simplified as a series of questions and communicated in a group of charts and tables intended to guide answers into certain established descriptors which provide a common language and consistency across different operations. What is the Avalanche Problem Type? Where in the terrain is the problem located? Sensitivity to Triggers? Spatial Distribution? etc. Each of the components of the model has a corresponding table used to support the forecaster in determining the appropriate descriptor. When the assessment is complete, the hazard can be expressed on this chart. Each oval represents an avalanche problem type and a range of possibilities.
Avalanche Hazard Graphic. Adapted from Conceptual Model of Avalanche Hazard, 2017 By: Statham, Haegeli, Greene, Birkeland, Israelson, Tremper, Stethem, McMahon, White, Kelly.
The Conceptual Model was designed to be used in all forecasting applications. In alignment with ISO31000, it starts with establishing the context. The context in this case, is the type of operation and the goal of the forecast, along with the temporal and spatial scale addressed by the forecast. Examples include public avalanche bulletins, industrial and transportation applications, and guiding operations. The CMAH provides a basis, or backdrop, for the forecaster to use when developing their products or making their risk analysis and evaluation as well as the common vocabulary for hazard assessment discussions. The graphical avalanche hazard chart is often included in internal documents or worksheets meant to provide documentation and support for forecasting decisions. This documentation also provides the forecaster with a detailed record of the decision-making process which can be examined for accuracy and used to identify potential errors or misjudgments. In the AIARE PRO Courses, students will use the CMAH as part of their daily hazard analysis meetings to support trip plans and terrain selection, and to determine what data and evidence should be collected in the field.
You can access the CMAH document via the linked PDF image below. This is a professional-level resource that should find its way into your personal library. After reading, you may also find the Canadian Avalanche Association's CMAH Flowchart Poster useful as a visual aid for the entire forecasting process.
Statham et. al 2017
International InfoEx CAA 2021
North American Public Avalanche Danger Scale 2022. Retrieved 20221003 from https://raw.githubusercontent.com/NationalAvalancheCenter/north-american-public-avalanche-danger-scale/main/1.%20Standard%20Danger%20Scale/For%20web/North%20American%20Public%20Avalanche%20Danger%20Scale.jpg