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Landslides

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Landslides

Landslides are simply the downslope movement of rock, debris or soil. Landslides can be caused by one or many factors, including: steep topography and high relief, weak fractured bedrock, earthquakes, river erosion, recent glacial retreat, intense rainfall and/or snowmelt events, disturbed groundwater flow, permafrost thaw and forest fires.

Landslides related to permafrost thaw are particularly widespread throughout Yukon (Lipovsky 2006 ). Several such landslides in south and central Yukon are viewed as unique because of their behaviour, longevity, large size and the fact that they have occurred naturally with no readily apparent disturbance that triggered them. YGS has performed long term monitoring at many of these landslides, including: 10 Mile Creek near Carmacks and several slides near Little Salmon Lake.

Landslides occur in a variety of settings in Yukon and have the potential to cause loss or life or property. By better understanding landslide distribution, morphology and hazards, we can contribute to safer planning, development, and recreation in the territory in the face of a changing climate.

 

Recent Projects:

  • Alaska Highway Corridor Studies: The Alaska Highway corridor has been the focus of much landslide hazard research in Yukon because it is so critical for transportation, infrastructure and community development in the territory. Sections of highway along southern Kluane Lake have been particularly impacted by landslides in the recent past (Clague 1981; Evans & Clague 1989). Landslide-specific research at YGS largely began in 2003, when a project was initiated to characterize landslide distribution and settings in the Alaska Highway Corridor (Huscroft et al. 2004a, 2004b). This work formed the foundation for landslide inventory, susceptibility, hazard and risk assessment work recently undertaken by the Geological Survey of Canada (Blais-Stevens et al. 2010, 2011). A number of site-specific studies have also been carried out by YGS in collaboration with various academic institutions to monitor key landslides and further investigate the nature, distribution and impacts of landslides throughout the corridor. These studies have included investigations near: Whitehorse (Brideau et al. 2011), Aishihik River (Brideau et al. 2005), Beaver Creek (CCORE 2007 ), and Destruction Bay (Lipovsky et al. 2004).

 

  • 2007 Mt. Steele Rock & Ice Avalanche: A catastrophic rock and ice avalanche occurred on the north face of Mount Steele, in Kluane National Park on July 24, 2007.  The ice and rock debris traveled up to 5.76 km with a maximum vertical descent of 2164 m, leaving a deposit 3.66 km2 in area on Steele Glacier. The landslide was detected on seismometers around the world, as it shook the earth with a force equivalent to a magnitude 5.2 earthquake. This was one of the largest rock avalanches onto glaciers ever documented in the Canadian Cordillera and YGS played a central role in investigating this landslide (Lipovsky et al. 2008b, 2008c , Brideau et al. 2010).

 

  • 10 Mile Creek Slide: Carmacks In June 2002, a large volume, extremely rapid debris torrent occurred 12 km southeast of Carmacks down 10 Mile Creek, which crosses the North Klondike Highway near a sign marking a local agate trail. The debris torrent traveled over 4.7 km down 10 Mile Creek and impacted the highway. Permafrost thaw contributed to the initiation of the slide and has caused ongoing instability in the source zone (Lipovsky et al. 2008a ). Landslide debris that was deposited along the length of the creek is continually remobilized by fluvial processes, causing ongoing problems with highway maintenance and flooding. This site has been monitored by YGS since 2003.

 

  • Permafrost-related landslides in central Yukon (Pelly River watershed and Little Salmon Lake): An inventory of permafrost-related landslides in the Pelly River watershed was conducted in 2006 (Lipovsky & Huscroft 2007) in response to local community concerns regarding potential impacts of landslide activity on water quality. A detailed study of landslides in the Little Salmon Lake area was conducted by Ryan Lyle from Queens University in 2004 and 2005 (Lyle 2006). Two of these slides, the “Magundy” and “YT” landslides, are large, active, permafrost-related landslides located near the east end of Little Salmon Lake ( Lyle et al. 2005, 2007). YGS monitored ground deformation at both of these sites by installing survey monuments and conducting differential GPS surveys (CCORE 2007). In 2008, another large landslide occurred on a nearby slope underlain by permafrost after a period of heavy rainfall (Brideau et al. 2010).

 

  • Dawson City area: The Dawson City landslide, also known as the Moosehide Slide, is a prominent large rockslide located at the northern edge of the city which occurred in prehistoric times. Gradual ground movements at the site have been monitored since 2003 by Marc-Andre Brideau, originally with Simon Fraser University, in collaboration with YGS (Brideau et al. 2006, 2007, 2012). Research has also been conducted in the surrounding areas to document numerous landslides that were triggered by permafrost thaw following extensive forest fires that burned near Dawson City in 2004 (Lipovsky et al. 2006; Coates 2008).

 

YUKON LANDSLIDES - Selected Publications & References

For more information on any of these projects contact Panya Lipovsky