The Hydrology, Snow and Glaciers of the Canadian Rockies in an Era of Global Change

The melt of snow and ice supplies freshwater for over half of humanity, and provides a vast proportion of the freshwater available for ecosystems, hydroelectricity, irrigation, industry, and communities in downstream regions. This water supply is threatened by climate warming which is reducing snowfall and increasing the atmospheric energy available to melt snow and ice. The Canadian Rockies are the hydrological apex of North America and the source of rivers flowing to three oceans. Here, over 60% of river discharge is supplied by the melt of snow and ice, and climate warming is proceeding faster than in other parts of the world. Climate variability is also increasing in these headwaters, and since the turn of the century some exceptionally low river flows and large floods have occurred. To understand these impacts, research by the University of Saskatchewan’s Centre for Hydrology and partners from its base at the Coldwater Laboratory in Canmore, Alberta has focussed on increasing our understanding of snow accumulation and melt processes in alpine and forested environments, glacier hydrology, and the role of soils, forests and wetlands in governing streamflow generation. This understanding has been used to develop computer simulation models of current and future hydrology that can be used for forecasting snowcover, floods and droughts, for prediction of future streamflows and for diagnosing how hydrological, glacier and ecological change are interacting with climate change to produce new behaviours in mountain rivers. These predictions can be used to develop water management solutions to some impacts of global change. They also show that resilience of hydrological systems to change is evident, but there remains a substantial risk of crossing tipping points in the near future that may lead to large changes and greater uncertainty in future water supplies.