Abstract: The Sunnydale landslide is a slow-moving rock-slope deformation on the western bank of the Yukon River directly across from Dawson, Yukon. While recent data suggest acceleration of the slide, which could pose a potential hazard to Dawson if the acceleration continues to the point of rapid failure, limited data precludes certainty on probability and timing of this occurrence. Field mapping allowed for documentation of road subsidence, expanding tension cracks, recent and ongoing rockfall and production of detailed geomorphological and surficial geology maps of the slide. Differencing from 2014, 2018, 2019, 2020 and 2022 aerial lidar data, and data from physical monitoring stations indicate current movement rates of up to 11 cm/yr across the slide area. Ongoing work including terrestrial lidar change analysis and installation of a near-real-time monitoring system in early 2023 will increase our understanding of current movement trends. Additionally, in-progress geologic dating of deformation features will further our understanding of the history and context of this feature on a geologic timescale.

Authors: Bodtker, J., Cronmiller, D.C, Bond, J.D. and Shugar, D.

NTS Mapsheet(s): 116B03

Citation: Bodtker, J., Cronmiller, D.C, Bond, J.D. and Shugar, D., 2023. The Sunnydale landslide, current understanding and research, Dawson (NTS 116B/3). In: Yukon Exploration and Geology 2022, K.E. MacFarlane (ed.), Yukon Geological Survey, p. 19–33.

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