Up to six years of data have been collected at seven stations within Yukon Geological Survey’s permafrost monitoring network between 2008 and 2013. Warm permafrost conditions (>-0.5°C) governed by latent heat effects exist at the Whitehorse, Watson Lake, Ross River School and Dawson School monitoring stations, while average permafrost temperatures in Faro are only marginally cooler at -0.6°C. Mean annual ground temperatures at the Beaver Creek and the Dawson dump forest monitoring stations are much colder at -2.9 and -2.0°C respectively. Most sites show either insignificant or very slight short term permafrost warming trends, although slight cooling is apparent at Ross River School, and rapid warming has occurred at Beaver Creek over the monitoring period. Opportunities to expand the network and collaborate with external parties operating similar monitoring stations should be further explored to facilitate more complete and representative reporting on the thermal state of permafrost in Yukon.

Placer mining has over a one hundred year history in the Yukon Territory. The majority of placer mining has taken place in the zone of discontinuous permafrost. Within the discontinuous permafrost zone, vegetated valley flats and north-facing slopes generally are underlain with permafrost. The permafrost thickness is highly variable and may reach depths of 60 meters. The active layer covering the permafrost also varies greatly in thickness. To access gold bearing gravels, the removal of extensive quantities of overburden is usually required. Once this insulative cover is removed, the thermal equilibrium of the permafrost is disrupted and thawing occurs. This affects the stability of soils and vegetation and slope failure may occur. The extent that exposed permafrost melts depends partly on the amount and form of ice content. As melting progresses, the potential for mass movement of soil increases. Melting permafrost usually results in a wetter environment than was initially present, which further affects the natural revegetation process. Bioengineering is the use of living plant materials to perform engineering functions such as erosion control and stabilization of steep slopes. Although bioengineering methods are now commonly used in the stabilization of steep problem slopes in more moderate climates (Polster, 1997), experimentation with these techniques in areas underlain with permafrost is still required. Advantages of using bioengineering systems are that they can be installed without machine access (which in permafrost areas would disturb the site even more), they strengthen with age, and they are less expensive than traditional hard engineering practices.

The Yukon Geological Survey has compiled a collection of papers, theses, reports and maps that describe permafrost in the Yukon. These reports have been footprinted and indexed to make them easier to find spatially. 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)

A drilling program was conducted in fall 2023 to install deep (up to 35 m) ground temperature monitoring boreholes in communities at risk from permafrost thaw. These boreholes will serve as long-term reference sites in both undisturbed and developed locations within or adjacent to communities. These boreholes also filled knowledge gaps that included the thickness of permafrost, and temperature data at the bottom of permafrost. Prior to this program, only 3 of the 34 permafrost-monitoring boreholes managed by the Yukon Geological Survey recorded temperatures through to the bottom of permafrost; furthermore, none of these boreholes are in the extensive discontinuous or continuous permafrost zones. Fifteen boreholes were drilled in five different communities across the Yukon: Dawson City, Mayo, Ross River, Beaver Creek and Haines Junction. Permafrost was encountered in 10 of the 15 boreholes, and the bottom of permafrost, or bedrock, was reached in at least one borehole in each community.

A database of geotechnical boreholes, ground temperature, and reports relating to permafrost in the Yukon.

The effects of permafrost degradation in Yukon have serious negative implications for the structural integrity of vertical infrastructure. This is especially pertinent for critical buildings such as hospitals, schools, etc., in small communities that are situated on top of warm, ice-rich permafrost. Projections of mean annual air temperature over the next few decades, based on regional climatic models, indicate that air temperature will rise, hastening the thaw of permafrost. The combination of rising of air temperatures and buildings situated on warm permafrost has prompted this investigation into the vulnerability of Yukon Government vertical infrastructure. The application of DC resistivity and ground penetrating radar in conjunction with borehole drilling indicates that in Dawson there is warm ice-rich permafrost beneath the Palace Grand Theatre; the Old Territorial Administration building is underlain by primarily unfrozen sediment; and permafrost under the St. Andrew’s Church is characterized by high variability. A deep active layer was observed at Ross River School and geophysical surveys indicate that warm water drainage from the roof is contributing to the thaw of the underlying permafrost.

The Yukon Geological Survey has compiled a collection of papers, theses, reports and maps that describe permafrost in the Yukon. These reports have been footprinted and indexed to make them easier to find spatially. 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)

This document comprises a compilation of technical reports for field investigations completed by Yukon University Research Centre (YRC) at seven case study sites that represent common permafrost environments in the greater Whitehorse area. This work was completed for Yukon Geological Survey (YGS) with core funding from Crown-Indigenous Relations and Northern Affairs Canada (CIRNAC) Climate Change Preparedness in the North (CCPN) program. The primary purpose of the report is to document results of field investigations (e.g., ERT geophysics, drilling and geotechnical laboratory analysis) completed by YRC at each site. Supporting background material and case study geological descriptions were prepared by YGS, along with general discussion relating to climate change and implications for development.

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The presence and proper classification of permafrost is essential to mine planning, operation, and abandonment in the Yukon Territory. This paper discusses the current state of practice regarding permafrost delineation and classification, presents information regarding design and monitoring of structures on permafrost (with particular reference to mining), and includes examples of Yukon and other northern mines where permafrost has affected operations. Permafrost in the Yukon is particularly sensitive to disturbance, as it is generally ¿warm¿ and discontinuous. It is therefore extremely critical that planning for new mines include provisions for the proper classification of permafrost on the mine property, as it will directly affect operations and abandonment of the site, with corresponding financial implications.