Contributing factors for landslides triggered by the November 2021 atmospheric river in British Columbia, Canada

More than a thousand geohazards were triggered by the mid-November 2021 atmospheric river in southern BC, Canada. We examined the contributing role of forest disturbances from wildfires, logging, and resource roads on the location of landslides. Geohazards occurred more frequently in burned areas and along forest harvesting resource roads, providing point sources of sediment that entered mainstem rivers. Geohazard mapping and lidar change detection revealed that bank erosion and lateral instability often occurred downstream of these mapped sediment sources.

Hancock (2025) Contributing factors for landslides triggered by the November 2021 atmospheric river in British Columbia, Canada, USGS Landslide Hazards Seminar, 26 March 2025.