posted March 27, 2025
Permafrost, Bones, & Landslides: Past and present climate change along the Dempster Highway
Wildfires, permafrost thaw, and landslides—how are they reshaping the Yukon?
Join Heather Clarke as she uncovers the dramatic impacts of climate change along the Dempster Highway, including the discovery of the largest collection of Pleistocene fossils found in the area!
About the Talk
The Yukon is experiencing impacts of climate change, including rising air temperatures, altered precipitation patterns, and increased wildfire activity. These changes are driving permafrost degradation and increasing landslide activity, posing significant risks to infrastructure. This study examines landslide triggers and morphology following a wildfire in permafrost terrain on the Dempster Highway, where active layer detachment (ALD) frequency increased 14-fold post-fire. ALDs exposed ice-rich permafrost, initiating retrogressive thaw flows (RTFs) that caused flooding near the highway, highlighting the cascading and compounding hazards associated with permafrost thaw. The RTFs exposed complex stratigraphy, representing over 100,000 years of accumulated ground ice, and colluvium and loess deposits, while also revealing the largest collection of Pleistocene fossils found on the Dempster Highway. This research reveals the local variability in ground ice within unglaciated areas and its implications for landslide susceptibility and RTF development, while also contributing to a better understanding of the region’s Quaternary history.
About the Speaker
Heather recently completed a Master of Science degree in the Earth Sciences Department at Simon Fraser University, where she studied post-wildfire permafrost landslides on the Dempster Highway. During her studies, she gained valuable field experience as a field assistant with the Yukon Geological Survey. She is passionate about landslide and hazard research and aspires to continue her work in the northern regions.