Influence of Precipitation, Temperature, and Climate Change on Landslide Hazards in Western Canada
Creators: Mirhadi, Seyed Nima
Publisher: name: University of Alberta Library
Year: 2024

<p>Canada experiences a significant number of landslides each year, posing substantial risks to safety, infrastructure, economic activities, and the environment. Over the last two and a half centuries, Canada has witnessed approximately 800 fatalities attributed to landslides, which has made landslides the nation&#39;s deadliest geological hazard. Furthermore, landslides are estimated to cost the country CA$200 - CA$400 million annually.<br>
This research aims to investigate the relationship between weather conditions (past and future), in particular precipitation, which has shown a high correlation with landslides in Canada from previous studies and landslides in western Canada. Due to the impact of various factors on landslides, such as geological and geotechnical conditions, the relationship between weather and landslides is unique in every region. This relationship has been studied in three locations: (1) The Transportation and Economic Corridors (TEC)’s C018 site, (2) The Yale subdivisions of the Canadian National (CN) Railway network in the Canadian Cordillera, and (3) Parts of the Battle, Red Deer, and Bow Rivers that are located within the Bearpaw Formation in Alberta, <br>
Different approaches and methodologies have been applied for each part of this study. In the first study at the C018 site, which is explained in Chapter ‎‎3, the antecedent weather signature that led to each recorded landslide has been investigated. Results show that antecedent precipitation, freeze-thaw cycles, and short-term temperature fluctuations play a significant role in landslide occurrences at the C018 site, and their effect can be quantified from a probabilistic approach. A clear weather signature has been identified for landslides occurring in the winter months. Moreover, statistical analyses on landslides occurring in spring and summer showed that if there is more than 20 mm of rainfall in 14 days, there is a 6% probability of a landslide, with a 0.1% probability of a landslide if there is less than 20 mm of rainfall in the preceding 14 days. This probabilistic approach provides a means to identify periods when the landslide hazard is 60 times higher than the other periods in spring and summer.<br>
In Chapter ‎4, I studied the cumulative effects of precipitation on the volume of landslides at the C018 site. The study looks at the correlation between precipitation and landslides between 2018 and 2022. The results show that a linear relationship can be approximated between the annual precipitation and the annual volume of landslides. This relationship is then used to estimate the annual volume of landslides by considering the projected annual precipitation based on the climate change models for the region.<br>
In the next step of understanding the relationship between landslides and weather, a statistical approach is applied to quantify the relationship between monthly precipitation and freeze-thaw cycles and rock fall frequencies for a section of a transportation corridor along the Fraser River in British Columbia, Canada (Chapter ‎5). von Mises distributions are used to find the best-fitted models to the monthly precipitation and freeze-thaw cycles, and proper relative weights are applied to the models to calibrate them to the rock fall monthly frequency. The calibrated model is then used with the climatic predictions for 2041-2070 and 2071-2100 to see how rock fall distribution will be affected due to climate change in the future decades. Results show that between 9% and 19% more rock fall is anticipated in future winters. Rock falls are expected to decrease in other months, especially in October, November, March, and April.<br>
Finally, in order to evaluate the relationship between climate conditions and landslide activity at a regional scale, I mapped the landslides on parts of the Battle, Red Deer, and Bow Rivers that are located within the Bearpaw Formation in southern Alberta, Canada, and compared their characteristics (Chapter ‎6). Further investigations into the long-term impact of climate on the formation of river valleys and the Bearpaw Formation reveal that climate is the main factor in causing variations in landslide occurrences across the study areas.<br>
This research enhances our understanding of landslide processes, and importantly, provides a means for predicting landslide frequency and volumes in the next decades as a consequence of climate change. This can prove to be very important information for agency resource allocation towards increasing resiliency in the built environment in the coming decades and promoting sustainable development.</p>