Landslides
It is difficult to predict future landslide trends in Quebec, given the small amount of data available and the sudden and very local nature of these phenomena.
Furthermore, the ability of climate models to accurately simulate soil water content is particularly difficult to assess in regions with winters, such as Quebec. However, it is possible to get a good idea of the impact of climate change on some of the factors that are conducive to landslides.
Projections of climate factors responsible for landslides in several regions of Quebec
The expected increase in extreme precipitation and storms in summer and autumn is likely to increase soil instability in landslide-prone areas in many parts of Quebec. This is particularly the case in the St. Lawrence Valley due to the predominantly clay composition of the soil. This type of soil will quickly become saturated if a large quantity of water enters it in a short period of time. This will make it more prone to losing its cohesion and stability, which can lead to landslides.
In winter and spring, the expected rising temperatures may influence the form of precipitation. Projections suggest that most of Quebec will experience more rain rather than snow. This would lead to more saturated soils, making them more unstable. As a result, the number of landslides would increase, particularly in vulnerable areas with clay soil composition, such as the St. Lawrence Valley.
In addition, freeze-thaw cycles are expected to occur earlier in the season across Quebec. This could also play an important role in the occurrence of landslides. Changes in these cycles can affect soil expansion and contraction, weakening the stability of slopes and embankments. As a result, landslides are likely to increase in vulnerable areas.
Northern environments
In the far north, the permafrost thawing process is already well underway and is set to continue due to the effects of climate change. The thawing of these soils, which used to be permanently frozen, leads to settling, subsidence and landslides as the soil loses its solidity. Thawing accentuated by warmer air and soil temperatures in northern Quebec could intensify and increase the number of landslides in these regions.
Furthermore, the projected increase in annual precipitation in northern Quebec may lead to increased water infiltration, exerting greater pressure on the soil and thereby increasing the number of landslides in the region.
Coastal environments
Projections indicate increased erosion and coastal flooding in the coastal regions of eastern Quebec. Given the significant role of erosion in destabilizing and weakening slopes, this situation is likely to lead to an increase in landslides in coastal environments.
In Quebec’s Côte-Nord region in particular, which is characterized by its numerous clay coastal cliffs, more ground movements linked to changes in freeze-thaw cycles are expected. This type of cliff is particularly sensitive to thawing, which can lead to mudslides and landslides.
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