7. The Johnstown Flood, wherein the South Fork Dam collapsed after being altered to suit the purposes of the local fishing club, killed more than a thousand people in 1889
The Johnstown Flood, also known as the Great Flood of 1889, was an event of May 31, 1889 caused by the breaching of the South Fork Dam and the resultant release of the Little Conemaugh River. After a sustained period of the heaviest rainfall recorded in the Midwestern United States, by the end of May the swollen Conemaugh River was almost overflowing. Despite the brave efforts of local workmen who noticed the dam was failing, sending unheeded warnings to Johnstown 14 miles away, just before 3 pm the dam collapsed. Demolishing houses in its path and decimating villages, an hour later the flood reached Johnstown.
Traveling at speeds of 40 miles per hour and with a height of 60 feet, many residents were crushed by the sudden waves. An estimated 2,209 people were killed by the floodwaters, including 314 at the Woodvale Iron Works. Despite the findings of the American Society of Civil Engineers, which concluded that the dam was so poorly designed to accommodate the local Fishing and Hunting Club that failure was inevitable, attempts by survivors to claim compensation were unsuccessful. Ruled an “act of God” by the courts, public outrage precipitated a major change in U.S. law to compel responsibility and liability in future cases of gross negligence.