“At the end of his memorandum, almost as an afterthought, Schleicher included a remark which, in retrospect, would take on a chillingly prophetic overtone. “A final point,” he said, “is that flooding in response to seismic or other failure of the dam—probably most likely at the time of highest water—would make the flood of February 1962 look like small potatoes. Since such a flood could be anticipated, we might consider a series of strategically-placed motion-picture cameras to document the process . . .” (emphasis added).”