October 13, 1952 Tsunami: Columbia River Valley, WA, United States

A tremendous landslide about 98 miles upsream of the Grand Coulee Dam, Washington, created a wave which broke tugboats and barges loose from their moorings at the docks of the Lafferty Transportation Company six miles up the lake at 11:45 A.M. The wave swept logs, driftwood and chunks of lakeshore sod over a large flat area above full lake level. (Reference #237)

Location, lake mile 98.37 right bank, Main terrace. This landslide occurred March 12, 1952, at 11:30 a.m. It was enlarged September 12, 1952, at 2:00 p.m., and again October 13, 1952, at 5:00 to 6:00 a.m. […] Lake waves and surges caused by this landslide broke tugboats and barges loose from their moorings at the docks of the Lafferty Transportation Co. 6 miles up the lake at 11:45 a.m. The stratigraphic sequence, the two-unit failures, and ground-water conditions are similar to those already described in this location. The October enlargement of landslide 257 caused a wave that reached higher on the opposite lakeshore than any wave caused by other landslides. This happened because the lake was full at the time of the slide. The wave swept logs, driftwood, and chunks of lakeshore sod over a large flat area just above full lake level. (reference #1695)

Note: location approximate