Debris flow hazard assessment in British Columbia

New regulatory guidance for assessment of debris flow hazards, prior to the approval of cutblock locations for forest harvesting activities in British Columbia, is reviewed. The framework is contrasted with the results of a database of 449 events recorded from cutblocks on the Queen Charlotte islands, B.C. Groundwater flow behaviour is described, and the temporal variation acknowledged. The role of a new, unified probabilistic framework in the assessment of initiation on open slopes and travel distance of events on open slopes or in gullies is then considered.