The Todagin Creek landslide of October 3, 2006, Northwest British Columbia, Canada

The Todagin Creek landslide is located at 57.61 degrees N 129.98 degrees W in Northwest British Columbia. A seismic station 90km north of the landslide recorded the event at 1643hours coordinated universal time (UTC; 0943hours Pacific daylight time (PDT)) on October 3, 2006. The signal verifies the discovery and relative time bounds provided by a hunting party in the valley. The landslide initiated as a translational rock slide on sedimentary rock dipping down slope at 34 degrees and striking parallel to the valley. The landslide transformed into a debris avalanche and had a total volume estimated at 4Mm(3). An elevation drop of 771m along a planar length of 1,885m resulted in a travel angle (fahrboschung) of 21.3 degrees. The narrowest part of the landslide through the transport zone is 345m. The widest part of the divergent toe of the landslide reaches a width of 1,010m. Landslide debris impounded a lake of approximately 32ha and destroyed an additional 67ha of forest. The impoundment took 7 to 10days to fill, with muddied waters observed downstream on October 13. No clear linkage exists with precipitation and temperature records preceding the landslide, but strong diurnal temperature cycles occurred in the days prior to the event. The Todagin Creek area appears to have an affinity for large landslides with the deposits of three other landslides >5Mm(3) observed in the valley.