[Dan] Boyer said, "It run over the top until it cut a channel, and then it ran out as fast as it could get out. It went out very fast, but it didn't burst out."
John Parke said, "It is an erroneous opinion that the dam burst. It simply moved away."
According to Ed Schwartzentruver, "The whole dam seemed to push out all at once. No, not a break, just one big push." (McCullough 100)
It is, therefore, safe to assert that the flood which poured through the break in the South Fork dam each second was equal to that which in the same space of time rushes over the Falls of Niagara.
...
...the total energy of the water was that of 20,000,000 tons falling 404 feet [onto Johnstown].
