Impacts of variations in snow cover on permafrost stability, including simulated snow management, Dempster Highway, Peel Plateau, Northwest Territories

Abstract

Permafrost conditions were examined near the Dempster Highway embankment on Peel Plateau, Northwest Territories. Ground temperatures were recorded in 2013-2015 at five sites at the embankment toe and at two sites in undisturbed (control) tundra. Annual mean ground temperatures at approximately 5 m depth ranged from −2.2 to 0.0°C at the embankment toe and were −1.8 and −2.6°C at control sites. Permafrost is degrading beside the road at four of five sites. Thaw depths are greater at the embankment toe, where deep snow accumulates, than in undisturbed tundra. A numerical model was used to examine the influence of varying snow cover properties on the ground thermal regime. Simulations indicated that delaying the onset of deep (1 m) snow accumulation and (or) prolonging the duration of the same total accumulation accelerates removal of latent heat from the active layer, increases sensible ground cooling, and results in reduced thaw depth. Furthermore, reducing snow depth and increasing snow density may rapidly raise the permafrost table, lower ground temperatures at the embankment toe, and cool permafrost at depth over several years. In consequence, mechanical snow removal and (or) compaction should be investigated as an active management strategy for mitigating permafrost degradation in ice-rich settings.Arctic Science Downloaded from www.nrcresearchpress.com by 44.224.250.200 on 07/04/20For personal use only. limite du pergélisol, baisser les températures du sol au pied du remblai et refroidir le pergélisol profond sur une période de plusieurs années. Par conséquent, on devrait considérer le déneigement mécanique et (ou) le compactage de neige comme stratégie active de gestion afin d'atténuer la dégradation du pergélisol en milieux riches en glace.Mots-clés : pergélisol, infrastructure, autoroutes, régime thermique, couverture de neige.

Canadian In Situ Snow Cover Trends for 1955–2017 Including an Assessment of the Impact of Automation

“…The depth of snow on the ground is an essential climate variable (GCOS, 2016) because of its widespread importance for applications, such as initialization of weather forecast models (Brasnett, 1999;de Rosnay et al, 2015), climate monitoring (Brown & Braaten, 1998;Vincent et al, 2015), estimation of design ground snow loads (Hong & Ye, 2014;Newark et al, 1989), impacts on ground heat transfer and permafrost (Goodrich, 1982;O'Neill & Burn, 2017), and multiple interactions and feedbacks in biophysical systems (Callaghan et al, 2011;Jones et al, 2000). In the International Classification for Seasonal Snow on the Ground (Fierz et al, 2009) snow depth is defined as the total height of the snowpack (i.e., the vertical distance from the ground to the snow surface) and is denoted here by the symbol SD with units of centimetres.…”

Consequences of permafrost degradation for Arctic infrastructure – bridging the model gap between regional and engineering scales

“…They result in an increased winter insulation where additional snow accumulates (e.g. at the embankment shoulder and toe, (Fortier et al, 2011;O'Neill and Burn, 2017). In contrast, snow clearance at the road surface leads to strong subsurface winter cooling.…”

“…Infrastructure embankments can also act as a dam that alters natural drainage networks, causing water to accumulate next to the road (Andersland and Ladanyi, 1994;de Grandpre et al, 2012;O'Neill and Burn, 2017). An elevated permafrost table in the embankment also hampers drainage, which may result in ponding at the embankment toe and increase the potential for thaw subsidence there.…”

“…LSMs have analysed consequences of permafrost degradation on Arctic infrastructure so far. Other model-based studies of Arctic infrastructure failure are rare and are usually limited to geotechnical site-specific studies (Fortier et al, 2011;Flynn et al, 2016;O'Neill and Burn, 2017).…”

Description and Quantification of Debris Tongue Movement in a Retrogressive Thaw Slump Using Aerial and Terrestrial Photogrammetry

“…This thesis investigates Slump CRB, a highly-active medium-sized retrogressive thaw slump located near the Dempster Highway within the Peel Plateau physiographic region. The Peel Plateau is characterized by rolling hills incised by deep river valleys (Lacelle et al, 2015;O'Neill & Burn, 2017). The area is underlain by continuous permafrost with an ice content that is likely highly variable and not well characterized (Lacelle et al, 2015).…”