An Overview of Some Recent Large Landslide Types in Nahanni National Park, Northwest Territories, Canada

Abstract

Large rock and soil landslides are an important part of the geodiversity in Nahanni National Park in Canada’s Northwest Territories. Here we describe five notable events, including two in soil, two in rock, and one involving rock and soil. Three of the events resulted in landslide dams. The Ram Plateau flowslide involved a collapse of a scree slope and fine textured soil over massive ground ice. This complex landslide continues to move in response to permafrost thaw and seasonal moisture. The Wrigley landslide is a large debris slide, involving thick till that dammed Wrigley Creek. The Cathedral Creek rock slide is a dip slope failure which dammed two large creeks. Cliff collapse of limestone on the Ram Plateau transformed into a rock avalanche, which dammed a stream. The Grizzly landslide involved both rock and soil. It is a large rock slide—earth flow in which, we suspect, undrained loading played an important role.