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)

The Yukon Geological Survey (YGS) has compiled available geotechnical and ground temperature data and related literature from government, industry and other contributors into the Yukon Permafrost Database. This paper reviews the database development process and structure, provides a snapshot of the primary datasets that have been loaded to date and discusses some of its limitations. The database is publicly accessible from an online portal (https://yukon.ca/en/yukonpermafrost) where data may be explored interactively in web maps, tables, and time series and ground temperature envelope graphics. Database contents are also available for download in a variety of formats. The Yukon Permafrost Database provides easily accessible data on permafrost distribution and thermal regime to support the assessment of thaw-related hazard and risk, and works towards the integration of disparate permafrost data at a territorial scale. The database will be maintained and updated regularly and YGS welcomes data contributions from government, industry and academic researchers to facilitate ongoing improvements to our collective knowledge 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 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.

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.

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.

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.

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)