Ruthless Tide by Today show cohost Al Roker is a solid work of nonfiction subtitled The Heroes and Villains of the Johnstown Flood, America's Astonishing Gilded Age Disaster. The book chronicles the man-caused disaster that killed more than 2,200 people in May 1889. Roker notes how the South Fork dam in Pennsylvania giving way unleashed some 20 million tons of water on the areas below it, with a current that traveled 30 miles an hour, with swells as high as 60 feet, down the narrow Conemaugh Valley, 14 miles to Johnstown.
The region was battered by a heavy storm, with the man-made lake filling up fast and by the time people at the dam in charge of it decided to try to remove the fishguard, it was too late, and the spillway had become clogged by other debris as well. Water went over the dam, cut grooves out of it, and it gave way, emptying the lake over the course of 30 to 45 minutes, leaving acres of mud. Johnstown was first pummeled with water and then fires started, with a stone bridge in Johnstown remaining standing, and exacerbating the death and destruction as it created a funeral pyre of sorts, with people and debris piling up and burning there.
It's also fascinating reading about the events after the disaster, including Clara Barton, founder of the American Red Cross coming on scene and establishing what the organization was capable of, and has continued to this day. Also, the disaster had effects on the legal system, creating greater liability where it due. While members of the South Fork club and people who ran it largely escaped liability in lawsuits filed, laws were changed to reflect that those who altered a natural environment had greater responsibility for any harm that was caused.