- May 2017
Slope instability occurs when mass-movement of rock, snow, or oil move downward due to gravity (Heritage). The types of slope instability are avalanches, landslides, rock fall, and rock slip, Slope instability can be detrimental depending on the infrastructure in that region. Water movement significantly contributes to slope instability. Water from snow or permafrost melt soaks into the soil, replacing air pockets and making the soil heavier (Nelson). Heavy soil on a steep slope can cause the soil to become dislodged and cause slope instability. The amount of water in the soil can also determine the slope angle. Too little water keeps the slope shallow, but some water can allow for a steeper slope due to changes in surface tension. Too much water caused a landslide because the excess water turns the soil into a fluid. Additional, unexpected permafrost melt can put too much water in the soil and lead to slope instability. Cold mountainous regions are often at risk for slope instability (Gruber). Permafrost exists in steep bedrock, which is categorized by a slope angle greater than 37 degrees. Ridges, spurs, and peaks are subject to increased permafrost melt that can lead to slope instability. Heat transfer by advection, or horizontal convection, is unpredictable and can occur through nearby ground water movement. This heat transfer leads to an increased rate of permafrost melt and can cause greater slope instability that heat transfer through the soil itself. Slope instability due to permafrost is directly influenced by climate change effects and could be detrimental to nearby populations and communities.
References: "Slope Instability." Heritage-Newfoundland and Labrador. Accessed May 06, 2017. http://www.heritage.nf.ca/articles/environment/slope-instability.php.
Nelson, Stephen A. "Slope Stability, Triggering Events, Mass Movement Hazards." Tulane EENS 3050. December 10, 2013. Accessed May 06, 2017. http://www.tulane.edu/~sanelson/Natural_Disasters/slopestability.htm.
Gruber, S., and W. Haeberli. "Permafrost in steep bedrock slopes and its temperature-related destabilization following climate change." JOURNAL OF GEOPHYSICAL RESEARCH 112, no. F02S18 (June 8, 2007). http://onlinelibrary.wiley.com/store/10.1029/2006JF000547/asset/jgrf280.pdf;jsessionid=4ACF5A28370C79D8882CD5745BE13C0B.f02t03?v=1&t=j2dliru8&s=9d3e555adabe5cef09dd53635b4830823d3afa9d.