Hebgen Lake, Montana, Earthquake August 1959. One of the large cracks in the concrete retaining wall of Hebgen Dam. The retaining wall, which is about 16 inches thick at the top and about 27 inches thick at the base, had a great many cracks in it, of which three or four were as large as this one. The retaining wall slumped, tilted forward, and was fractured during the earthquake. Water seeped through these fractures. August 1959.
Digital File:wij00087

ID. Witkind, I.J. 87ct