February 16, 1953 Tsunami: Columbia River Valley, WA, United States

A series of landslides on Roosevelt Lake, Washington, near the February 14 slide site generated at least ten waves which crossed the lake and reached the maximum lake shore level 16 feet above the existing lake level. One exceeded the sixteen foot level. A block of material was observed as it dropped into the lake and made a mound of white water one-fourth as high as the terrace. The waves crossed the lake. The wave fronts were vertical walls of water; some had a dome-shaped surface just behind the vertical wall. On the average the waves crossed the lake in one and one-half minutes or at a rate of 4,000 feet per minute. This is in good agreement for a lake depth of about 140 feet indicating the wave traveled as a gravity wave. (Reference #237)

Reference #1695:

The initial failure mass at 8:15 p.m., February 14, 1953. Blocks of earth caved into the lake intermittently until February 19. Thunderous noises accompanied the initial failure and the subsequent caving. Many large waves were formed on the lake.

February 16, 1953, 3:43 a.m. Initial failure. The noises from this slide awakened everyone in the Z. A. Carson household across the lake. Caving and enlarging continued throughout the morning. At least 10 waves crossed the lake and reached the maximum lake-level shoreline, or 16 feet in height. One wave was higher and reached above the high waterline. A block of material was observed as it dropped into the lake and made a mound of white water one-fourth the height of the terrace. Waves crossed the lake. The wave fronts were vertical walls of water; some waves had a dome-shaped surface just behind the vertical wall. On the average the waves crossed the lake in 1% minutes, or at a rate of 4,000 feet per minute.

Note: location approximate