The large earthen dam had originally been built by the Pennsylvania state authorities forty years before, to feed the canal system, just in time for the canals to be replaced by rail. It was sold to a group of Pittsburgh investors who converted the lake and dam into an exclusive leisure resort - mainly fishing, no doubt some hunting as well. Members included that fabulously wealthy Andrew Carnegie, banker and future Treasury Secretary Andrew Mellon and future Attorney-General and Secretary of State Philander Knox. But they did not maintain the dam properly, patching it with mud and straw. On 29 and 30 May 1889, that part of Pennsylvania received the highest rainfall ever recorded there, around 200 mm.
The hunters and fishers spotted that there was a problem on the morning of the 31st, and did their best to shore up the crumbling dam, also telegraphing warnings downstream to Johnstown, where nobody listened because they had had too many false alarms before. The dam broke and 14.5 million cubic metres of water tipped down the narrow valley, hitting Johnstown with a wall of liquid 18m high in places, travelling at about 60 kph. It had already smashed through the iron works at nearby Woodvale. The valley was devastated.
Much debris was found as the clearing up began, including this poignant story of a wandering horse and its lost owner, reported in the Indiana Weekly Messenger of 5 June 1889:
A Treacherous Pole.
A horse, supposed to be the one upon which Robert Wickersham was riding when the flood overtook him and he climbed a telegraph pole, was found upon the premises of a farmer back of Woodvale. The horse had apparently been in the woods for several days, and was almost starved. Upon his back was a saddle, which was supposed to be owned by Mr. Wickersham. The farmer will keep the horse until called for. Mr. Wickersham was the chief draughtsman at the Johnson Steel company's works.Wickersham's name was actually Richard, not Robert. He was one of the 980 victims of the flood whose body was never found. He is recorded as 26 years old in the accident reports, but in fact was only 24. Born in Pittsburgh, he did not have time to go very far in his life; Johnstown is a bit over 100 km to the east of the Steel City. His oldest surviving brother administered what there was of his estate (including, I suppose, the unfortunate horse). Two years later, in 1891, their sister Rebecca married Henry Deming Hibbard (an iron man, like the Wickershams' father Samuel) and in due course Rebecca and Henry became my great-grandparents. Poor Robert or Richard Wickersham was my grandmother’s uncle, though she was not born until 1899, ten years later, and she would have known him only as one of several dead members of her parents' generation.
Wickersham was seen to climb up the pole until he reached the cross-arms, where he rested. He apparently thought he was safe, and yelled to a number of people to run up the hill out of the water's reach. In a few minutes the pole "sagged" and tipped over. Wickersham still clung to it and the pole began to drop lower and lower. All of a sudden the pole give a lurch and fell into the water. Wickersham disappeared from view and was seen no more. The people living in the row of frame houses on the hillside opposite saw him as he went down.
Even so, it's an unexpectedly powerful sense of connection to a massive disaster. Look after those dams, folks...