The residents of the Mill River Valley in Massachusetts had been nervous about the reservoir dam for years. Indeed, one man often rose on rainy nights and rode up to check its safety.
Eventually, on one terrible morning, their fears were proven right - 139 people died and 740 homes were destroyed in a wall of water and debris.
The story of these people, the heroic riders who rode ahead of the water to give warning and the tragic outcome of the 1874 disaster are well-documented by Elizabeth M. Sharpe in her book "In the Shadow of the Dam."
A historian who grew up hearing how the flood destroyed her grandfather's shop, Sharpe has culled local records, dozens of newspapers and letters written by local residents to piece together the story of a disaster that has gotten little attention.
Like the better-known Johnstown, Pa., flood 15 years later, the Mill River disaster was caused by the failure of a poorly built and poorly maintained private dam. And, as in the Johnstown event, no one responsible for the failure ever paid a dime in penalty.
The dam was built to provide water power for several local factories. The factory owners paid for it, but skimped on the costs, using an inexperienced designer and contractors who weren't familiar with dam construction, Sharpe reports.
The result was predictable. As she quotes a juror at the inquest: "I do not believe, however much we are an evolved species, that we are derived from beavers; a man cannot make a dam by instinct or intuition."
Due to that lack of skill, water undercut the tall earthen dam causing it to fail early on the morning of May 16, 1874, sending 2.5 million tons of water plus debris into the towns of Williamsburg, Skinnerville, Haydenville and Leeds.
George Cheney, the dam's attendant, lived on the hill next to the dam and saw the collapse beginning. Mounting a horse, he sped downstream trying to warn people; it was a ride that saved many lives.
Describing the failure, Cheney's wife, Elizabeth, said the dam "seemed to burst all at once, from the bottom, where the earth seemed to be lifted up."
Witnesses described a wall of water between 20 and 40 feet high and 300 feet wide tumbling over itself as it came down the valley collecting houses, trees and debris. Much of what the wave carried was sediment from the bottom of the reservoir, a deep layer of rotting organic matter that emitted an odor people could smell a mile away.
That wave tumbled factories, blew homes to pieces and swallowed lives in an instant. Of the 139 dead, some 43 were younger than 10 and killed at home with their mothers.
Five entire families were wiped out - the Birminghams and Johnsons in Williamsburg, and the Fitzgeralds, Patricks and Fennesseys in Leeds.
Today, the river flows quietly, no longer a source of terror. The ruins of the dam are still there, writes Sharpe, and one can walk out onto remains that end suddenly, where a viewer can look down four stories at the brook trickling through below.