Citation

Geertsema M, Menounos B, Bullard G, Carrivick JL, Clague JJ, Dai C, Donati D, Ekström G, Jackson JM, Lynett P, Pichierri M, Pon A, Shugar DH, Stead D, Del Bel Belluz J, Friele P, Giesbrecht I, Heathfield D, Millard T, Nasonova S, Schaeffer AJ, Ward BC, Blaney D, Blaney E, Brillon C, Bunn C, Floyd W, Higman B, Hughes KE, McInnes W, Mukherjee K, Sharp MA. Geophys. Res. Lett. 2022; 49(6): e2021GL096716.

Copyright

(Copyright © 2022, American Geophysical Union)

DOI

10.1029/2021GL096716

PMID

unavailable

Abstract

We describe and model the evolution of a recent landslide, tsunami, outburst flood, and sediment plume in the southern Coast Mountains, British Columbia, Canada. On November 28, 2020, about 18 million m3 of rock descended 1,000 m from a steep valley wall and traveled across the toe of a glacier before entering a 0.6 km2 glacier lake and producing >100-m high run-up. Water overtopped the lake outlet and scoured a 10-km long channel before depositing debris on a 2-km2 fan below the lake outlet. Floodwater, organic debris, and fine sediment entered a fjord where it produced a 60+km long sediment plume and altered turbidity, water temperature, and water chemistry for weeks. The outburst flood destroyed forest and salmon spawning habitat. Physically based models of the landslide, tsunami, and flood provide real-time simulations of the event and can improve understanding of similar hazard cascades and the risk they pose.

Language: en

Keywords

deglaciation; glacial lake; hazard cascade; landslide; outburst flood; tsunami