A deglacial hazard cascade exemplified by the landslide, tsunami and outburst flood at Elliot Creek, Southern Coast Mountains, British Columbia, Canada

We describe and model the evolution of a recent landslide and outburst
flood in the southern Coast Mountains, British Columbia, Canada. About 18
Mm3 of rock descended 1000 m from a steep valley wall and traveled across
the toe of a glacier before entering a 0.6 km2 glacier lake and producing
a >100-m high wave. 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 detritus, and fine sediment entered a fjord
where it produced a 70-km long turbidity current and altered turbidity,
water temperature, and water chemistry for weeks. The outburst flood
destroyed forest and culturally significant salmon spawning and rearing
habitat. Physically based models of the landslide, the displacement wave,
and the flood provide real-time simulations of the event and can improve
understanding of similar hazard cascades and the risk they pose.