Characterization of the Zymoetz river rock avalanche

On June 8, 2002, the Pacific Northern Gas pipeline in the Zymoetz River valley was severed over a distance of tens of meters by a large debris flow. The event initiated as a rock avalanche in Glen Falls Creek, a tributary of the 6 3 Zymoetz River. The rock avalanche involved I XI 0 m of volcaniclastic bedrock, and travelled through a complex flow path, to finally deposit a large fan in the main Zymoetz River. Approximately half of the debris volume was deposited in the cirque basin at the head of the valley, with the rest deposited in the channel, and the fan. Photoanalysis software has offered insights into the grain size distributions throughout the deposit. Application of the modelling programs DAN-W IDAN3D has significantly increased our understanding of the dynamics of the event.