The unusual Brenot Creek landslide, northeastern British Columbia

The Brenot Creek landslide in northeastern British Columbia initially failed in the early 1980s and was relatively inconspicuous until a failure in August 2014 commenced a period of sustained landslide activity. Paleovalleys, drainages that were present prior to the last glaciation, had significant accommodation space and were infilled with thick accumulations of glacial sediments influenced by the Laurentide Ice Sheet and multiple advances of the Cordilleran Ice Sheet. The Brenot Creek landslide is seated within a previously unmapped paleovalley. Eight stratigraphic units above bedrock have been defined representing three glacial cycles, which suggest refinements to the regional stratigraphy and glacial history. Failure of the Brenot Creek landslide is caused by internal erosion of silty sand advance phase glaciolacustrine deposits. The developed geological model is applied together with the evolution of the landslide and the mechanisms of internal erosion to understand and account for the landsliding.