Caution: Road Hazard

Newswise — Global climate change may open up a new sea route in the Canadian arctic with potential as an alternative transportation corridor, but this new mobility by sea may be offset by highway blockages and damage due to the same warming influence, according to a study presented at the Canadian Hazard and Risk Research Network annual meeting last week.

The report, 'A regional characterization of landslides in the Alaska Highway corridor, Yukon,' was prepared for the Yukon Geological Survey (YGS) by University College of the Cariboo geographer Crystal Huscroft, with Panya Lipovsky, YGS geomorphologist and GIS specialist, and Jeff Bond, YGS surficial geologist. It describes the settings, causes and geological controls of landslides in the Alaska Highway corridor, noting that the climate's local and regional influence on hydrology, fire frequency and permafrost distribution affects landslide processes.

Current climate change projections, which call for warmer temperatures and increased precipitation for the Yukon in the next half century, have a variety of anticipated effects, among them increased incidents of intense snowmelt and/or precipitation events, river migration, permafrost degradation or forest fires, which in turn may lead to an increase in landslide frequency and/or magnitude.

Furthermore, the most significant impact of increased landslide activity may not be a direct impact. Rather, said the report's authors, increased sediment input from landslides will likely increase stream channel instability and flooding, an effect particularly acute in the vicinity of alluvial and colluvial fan complexes along Kluane Lake, where highway maintenance is already a challenge.

Climate events like intense rainfall and rapid snow melt, along with seismic events act on areas with shallow bedrock or permafrost, unconsolidated sediment on steep slopes, or weak bedrock, cause river erosion, modern stream incision or the degradation of ice-rich permafrost, which in turn cause landslides and debris flows which are capable of damaging settlements and transportation routes.

The report, the Yukon Geological Survey's Open File 2004-18 (65 p) is available for free download (43.7 Mb) in portable document format (pdf) at: http://www.geology.gov.yk.ca/publications/openfile/2004/of2004_18.pdf