CRYOSPHERIC CONDITIONING OF LANDSLIDES IN WESTERN CANADA AND ALASKA (Invited Presentation)

Cryospheric changes may be contributing to landslide size and magnitude in western Canada and Alaska. Placing large rock slide initiation zones in recently deglaciated areas is relatively simple. Glacier changes are very recognizable on coarse satellite imagery. Establishing linkages between slope instability and mountain permafrost degradation is much more difficult. Permafrost is a thermal state, its presence or absence much less obvious that of a glacier. Nonetheless advances in permafrost distribution mapping, rock temperature data, and frozen rock mechanics suggest landslides may be increasing due to permafrost thaw. On larger scales, the repositioning of landscape elements may be giving cryospheric landslides a much greater impact zone. For example, the retreat of valley glaciers may bring glacial lakes and fjords closer to steep slopes, increasing the likelihood of landslide tsunamis or rock slide - debris flows. Here I give an overview of some recent cryospheric landslides and their consequences.