Distribution and frequency of debris flows triggered by atmospheric rivers, Fraser Canyon, British Columbia

Debris flows, common in mountainous terrain worldwide, are often primarily attributed to intense precipitation events, leading to rapid downslope transferals of sediment from hillslopes to channels and affecting fluvial processes. In southwestern British Columbia, atmospheric rivers are expected to become more intense and frequent, leading to an increase in debris flows. Despite this increase, the public and governing authorities lack awareness of these hazards. To enrich our understanding of these hazards, this research aims to investigate the impact of debris flows triggered by atmospheric rivers along the lower Fraser Canyon through satellite imagery and historical air photo analysis. The spatial distribution, frequency, and geomorphic changes caused by these events are examined, with a focus on the formation of Tikwalus Rapid. The slopes and areas between affected and stable tributary basins are compared to identify distinct characteristics of basins prone to these hazards. The findings enhance our understanding of landslide risks and their potential impacts on river systems.