Evaluating Impacts of Climate Change on Snowmelt and Rain-on-Snow Events Across Canada

September 26, 2024

In Canada, dams and water management infrastructure in high-latitude and high-elevation areas, must be designed to withstand floods caused by snowmelt events (snowmelt-only and rain-on-snow) in addition to rain-only events. The effects of climate change on these events, over both operational and post-closure timescales, are important to consider when building or maintaining resilient facilities. Snowmelt events often govern hydrotechnical designs in Canada; however, estimating snowmelt in a changing climate is complex and lacks guidance. Underestimates of design floods present considerable risks for dam owners, while overestimates result in considerable costs. This paper applies a quantitative method for evaluating the impacts of climate change on snowmelt events to several sites across Canada, including two in British Columbia, one in Alberta, one in the Northwest Territories, and one in Ontario. This paper builds on previous work by the same authors, who established a method for evaluating the impacts of climate change on snowmelt and rain-on-snow events. The method evaluates climate change impacts using a continuous simulation snowmelt model and downscaled Global Climate Model (GCM) data to quantitatively model the joint probabilities of snow cover, warm temperatures, and rainfall coinciding (and future changes to these probabilities). The sites presented in this case study cover a range of elevations, latitudes, and storm mechanics and seasonality. While the results of this paper are site specific, the extended geographic range of the case studies will help dam owners understand the potential range of impacts of climate change.

Clark, S. and N. Whitmore. 2024. “Evaluating Impacts of Climate Change on Snowmelt and Rain-on-Snow Events Across Canada,” in Proceedings of the CDA Annual Conference, 22-25 September 2024. Niagara Falls, ON: Canadian Dam Association.