A reconnaissance inventory of permafrost-related landslides in the Pelly River watershed was conducted in 2006, largely in response to local community concerns regarding the potential impacts of climate change on slope stability and possible effects on water quality. Using aerial photograph analysis, satellite imagery, and visual inspection from a fixed-wing aircraft, over 100 permafrostrelated slides were located near the Pelly and MacMillan rivers and various tributaries. Basic geomorphic characteristics were determined for many of the failures based on analysis of remote sensing data, and reviews of existing literature and surficial geology maps. Most of the landslides identified were small active-layer detachments and retrogressive thaw failures. Several large failures also illustrate important characteristics associated with permafrost-related landslides, including their source-area setting, triggers, high mobility, the longevity of their activity and their ability to impact very large areas. The nature and distribution of the identified failures highlights a number of implications for land-use in central Yukon and emphasizes the need for enhanced methods of permafrost detection and regional mapping in the Territory.

Local-scale surficial geology mapping was completed as part of a community hazards mapping program coordinated by the Northern Climate ExChange (Yukon Research Centre, Yukon College). This program assesses potential landscape hazards under changing future conditions by incorporating a variety of data sets, including surficial geology, topography (slope and aspect), permafrost distribution, site-specific permafrost data (e.g. ground penetrating radar, electrical resistivity tomography and borehole data), analyses of past hydrological and climatological trends, and future climate projections. The surficial geology map describes surface landscape features, sediment texture, genetic material, surface expression and geomorphological processes. Detailed descriptions of local surficial geology and hazard analysis methodology are presented in the accompanying report. The accompanying landscape hazard classification map identifies existing and potential geological hazards such as landslides, permafrost stability and flooding; the hazard map is presented in stoplight colours to provide an intuitive tool for community decision makers aiming to incorporate an adaptation planning framework into existing land use management practices.

The Dempster Highway, Canada’s most northern highway, is an all-weather gravel road through a landscape that remains mostly wilderness. From its southern starting point (Km 0) east of Dawson City, Yukon, the highway crosses the Arctic Circle (latitude 66°33’ North) at Km 405. It passes from Yukon into Northwest Territories at Km 465, and terminates in Inuvik at approximately Km 717.5. The road also summits the continental divide between the Pacific and Arctic oceans (Km 82) and traverses two mountain ranges (Ogilvie and Richardson mountains) of the Canadian Cordillera. It is a spectacular multi-day journey, so take some time to enjoy it!

Permafrost is integral to the landscape of the Yukon, and influences hydrology and ecology, and impacts infrastructure. Accelerated permafrost thaw due to climate change poses significant challenges, particularly for the Alaska Highway, a vital transportation route. This study investigates how thawing permafrost may relate to ground instability, resulting in cracks and deformations along the highway. Thermal infrared imaging, and light detection and ranging (lidar) mounted on remotely piloted aircraft systems (RPAS), along with ground surveys, were completed at three localities along the Alaska Highway between the White River and the community of Beaver Creek, Yukon. Through these surveys, temperature variations and topographic changes were examined. At many locations, the damage is characterized by a 1 to 2 m-wide subsidence feature running longitudinally along the middle of the highway. Associated with these zones of subsidence are potholes, as well as longitudinal and transverse cracks. In places, the system of cracks extends to the edge and shoulder of the highway, suggesting that the cracks and deformation are currently active features.

This guidebook describes the rocks and landforms along the Dempster Highway. The southern terminus of the highway is located near Dawson City in west-central Yukon. A drive along the Dempster Highway takes you from its junction with the South Klondike Highway (Hwy 2), 717 km northeastward to Inuvik, Northwest Territories. On road maps this is Highway 8 in Northwest Territories, and Highway 5 in Yukon. The Dempster Highway traverses diverse geological features and many contrasting landscapes. It passes rocks created hundreds of millions of years ago, mountain ranges with a complex history of continental collision, hints of the energy resources at depth, and evidence of recent glaciations. The guide is an update and expansion of a guide produced for a fieldtrip sponsored by the Canadian Society of Petroleum Geologists. It also incorporates information from a guide by Tarnocai et al. (1993) and observations of the contributors in 2005 and 2006. In this guidebook you will find an introduction to the general bedrock geology, glacial history and mineral resources of the area, followed by a road log, and a glossary explaining geological terms.

Landscape hazard maps were completed as part of a community hazards mapping program coordinated by the Northern Climate ExChange (Yukon Research Centre, Yukon College). Potential landscape hazards were assessed under changing future conditions by incorporating a variety of data sets, including surficial geology, topography (slope and aspect), permafrost distribution, site-specific permafrost data (e.g. ground penetrating radar, electrical resistivity tomography and borehole data), analyses of past hydrological and climatological trends, and future climate projections. The landscape hazard map identifies existing and potential geological hazards such as landslides, permafrost stability and flooding. The hazard map is presented in stoplight colours to provide an intuitive tool for community decision makers aiming to incorporate an adaptation planning framework into existing land use management practices. Detailed descriptions of data inputs and hazard analysis methodology are presented in an accompanying report (available for download from [https://data.geology.gov.yk.ca/Reference/68408](https://data.geology.gov.yk.ca/Reference/68408) ). An accompanying surficial geological map also describes detailed landscape characteristics such as surface landscape features, sediment texture, genetic material, surface expression and geomorphological processes (available for download from [https://data.geology.gov.yk.ca/Reference/68408](https://data.geology.gov.yk.ca/Reference/68408) ). Distributed from [GeoYukon](https://yukon.ca/geoyukon) by the [Government of Yukon](https://yukon.ca/maps) . Discover more digital map data and interactive maps from Yukon's digital map data collection. For more information: [geomatics.help@yukon.ca](mailto:geomatics.help@yukon.ca)

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The following report describes the settings, causes and geological controls of landslides in the Alaska Highway corridor. Although diverse geologic, geomorphic and climatic environments exist in the region, most landslides are related to the presence of shallow bedrock or permafrost, unconsolidated sediment on steep slopes, weak bedrock, groundwater hydrology, river erosion or the degradation of ice-rich permafrost. Where geologic controls provide appropriate settings, intense rainfall, rapid snow melt and seismic events play important roles in triggering failures. Rainstorms that reach thresholds of combined intensity and duration have triggered abundant shallow landslides within the corridor. Debris flows have historically posed the highest risk to lowlying regions and are capable of damaging settlements and transportation routes. The Shakwak Valley has the highest concentration of landslides within the corridor due to the abundance of steep slopes, high relief and widespread discontinuous permafrost. In Wellesley Depression, shallow permafrost and its subsidence has an important influence on slope instabilities. Landslides in the Yukon Plateau primarily relate to the presence of silt- and ice-rich tills on steep valley sides as well as the incision of fine-grained lacustrine terraces in valley bottoms. Debris flows after intense rainfall events are the most common form of landslide in the Kaska Mountains. Finally, in Liard Lowland, failures associated with glacial meltwater and modern stream incision are the most common landslide events. Permafrost plays an important role in landslide processes in the corridor due to its influence on soil moisture, drainage and strength. Slopes composed of icy sediment that have been burned by forest fires are particularly vulnerable to rapid mass movements due to permafrost degradation. The consequences of the dramatic increase in landslide potential after fire should be considered in local fire management plans. The climate¿s local and regional influence on hydrology, fire frequency and permafrost distribution greatly affects landslide processes. Current climate change projections call for warmer temperatures and increased precipitation for the Yukon in the next half century. Among the anticipated effects of global warming in southern Yukon, increased incidents of intense snowmelt and/or precipitation events, river migration, permafrost degradation or forest fires may lead to an increase in landslide frequency and/or magnitude within the settings described in this report. The most significant impact of increased landslide activity may not be a direct impact. Rather, increased sediment input from landslides will likely increase stream channel instability and flooding. This would be particularly acute in the vicinity of alluvial and colluvial fan complexes along Kluane Lake where highway maintenance is already a challenge.

The Yukon is experiencing impacts of climate change, marked by elevated annual air temperatures, alterations in precipitation patterns and increased wildfire activity. These changes can lead to permafrost degradation, impacting highways and community Infrastructure. In July 2017, a wildfire burned a slope in permafrost terrain above the Dempster Highway in the Yukon. In the years following the wildfire, two types of permafrost-related landslides have been observed on the slope. Active layer detachment activity was highest in the first year after the landslide, possibly influenced by warm temperatures and rainfall events. Retrogressive thaw flow slides formed in 2019 in areas of ice-rich permafrost and are still active in 2023. Deposition of sediment and influx of water has resulted in flooding near the highway, further degrading the permafrost in the valley bottom. This study characterizes the landslide timing and morphology following a wildfire on permafrost terrain, and investigates potential triggers and controls.

Five case studies of recent landslides in southwestern Yukon Territory illustrate the role of permafrost in landslide processes of the region. In the Marshall Creek basin, permafrost degradation after recent forest fires caused numerous debris flows near the valley bottom. Similarly, on Haeckel Hill, firerelated deepening of the active layer has facilitated active layer detachment slides on upper hillside slopes. In the Kluane Range, the interface between frozen and unfrozen ground appears to control the depth of movement for active layer detachment slides and debris flows along Silver Creek. The failure mechanism on Mount Sumanik is controlled by a frozen substrate, which contributes to a reduction in drainage and elevated pore-water pressure. Lastly, thawing of segregated ice has caused a thaw slump of fine-grained sediment in lacustrine terraces along Takhini River.