November 28, 2020 Tsunami: Elliot Creek, Bc, Canada

Reference #13180:

On 28 November, 2020 a seismic event detector network recorded a landslide within 60 km of Elliot Creek, but its location was unclear until forestry workers discovered its aftermath some two weeks after the event.

Post-event observations and subsequent modeling reveal that the slide mass moved nearly 1000 m downslope in about 70 seconds. About 40% of the fragmented rock mass came to rest on the toe of the glacier above the lake. The remaining debris ran up the distal slope on the west side of the valley before entering the lake and creating a tsunami that exceeded 100 m in height.

Some 13.3 million m3 of fragmented and bulked landslide debris traveled into the lake, forming several islands and reduced its area from 0.62 to 0.51 km2. Sediment eroded from the shoreline by the push wave (as deep as 12 m) contributed to lake filling. We estimate that approximately 15 million m3 of water left Elliot Lake during the landslide and tsunami.

Note: runup observations (including a max of 114 m) not included in historical database due to lack of instrumental recording or eyewitness accounts.