| Abstract | The remote valleys and high mountain areas of western Canada have experienced accelerated economic development only in recent years. Although there have been occasional mass movements of destructive
impact in this region in the past, the short history of human settlement makes it difficult to properly evaluate the potential hazard and appropriate countermeasures during future development of steep mountainsides and narrow valleys. A large body of
documented experience from long-inhabited mountain regions, notably the Alps of Europe, suggests that major mistakes can be avoided if this experience is used properly. Most destructive mass movements are complex and related to mountain torrent
systems and instabilities of steep bedrock slopes. They can be conveniently grouped into (1) de bris flows from surficial deposits, (2) de bris flows from bedrock failures, (3) mass movements on volcanoes, (4) glacier-related mass movements, and (5)
rockfalls and rock avalanches. Each of these requires a different type of hazard appraisal and particular set of remedial or preventive measures. The range of possible destructive impacts and appropriate countermeasures are illustrated with 137 case
histories from the Alps which are presented in a coherent geological-climatic framework transcending the traditional political boundaries. Analysis of these case histories, combined with insights gained elsewhere, is used to outline the application
of active measures (forestry, control works, protective works), passive measures (zoning, planning), monitoring, and acceptance of risk. The decisions regarding which active or passive measures should be applied and what Level of risk is acceptable
are based on (1) information on recurrence and magnitude of mass movements and (2) a broad social-economic consensus. |