Avalanche Starting-Zone Analysis by use of a Knowledge-Based System

This paper presents the first step in the development of a new kind of computer-based tool which can help a specialist consultant in avalanche path analysis, a knowledge-based or expert system. In considering an avalanche path, the specialist often needs a simulation of possible avalanches on this path in order to obtain data for probable velocities and pressures. Use of classical numerical tools by an engineer requires a great deal of experience and knowledge. Such knowledge exists, but until the development of knowledge-based systems no computer-based tool was available. After a short review of such systems, we describe a knowledge-based system currently being developed in CEMAGREF. Its problem-solving environment includes methods of analysis developed by a senior consultant, and also numerical and qualitative models. In the first step, which is presented here, it analyses the starting zone of an avalanche path. By means of a digital terrain model and a description of vegetation and main ridges (a model which still needs to be improved) this system can make use of the experience of specialists to produce an avalanche-starting simulation based on specified meteorological conditions. Quite simple rules are employed in order to take into account snow drift. First results are shown on accompanying maps of this qualitative modelling and these will need to be tested for validity.