Floods in the United States before 1901
Floods in the United States before 1901 is a list of flood events that were of significant impact to the country, before 1901. Floods are generally caused by excessive rainfall, excessive snowmelt, and dam failure.
The Kankakee Torrent was a catastrophic flood that occurred between 14,000 and 18,000 years ago, resulting from the breach of a large glacial lake formed by the melting of the Wisconsin Glacier. The origin of the flood may have been prehistoric Lake Chicago, it may have come from further east, near what is today the center of the Lower Peninsula of the state of Michigan. The torrent carved out a channel that is currently followed by the Kankakee River and Illinois River. It also appears to have pushed the course of the Ohio River further south and the Mississippi River further west. The bluffs carved by the torrent can be seen at Starved Rock State Park and Kankakee River State Park. In both parks, smaller streams flow over waterfalls before they join the main river, phenomenon known as hanging tributaries.
Glacial River Warren drained Lake Agassiz in central North America through a series of floods about 9,700 years ago. The enormous outflow from this lake carved a broad valley now occupied by the much smaller Minnesota River and the Upper Mississippi River. Agassiz was a huge body of water, up to 600–700 feet (~200 m) deep, and at various times covering areas totaling over 110,000 square miles (~300,000 km2). Blocked by an ice sheet to the north, the lake water rose until about 9,700 years ago, when it overtopped the Big Stone Moraine, a ridge of glacial drift left by the receding glacier, at the location of Browns Valley, Minnesota. The lake's outflow was catastrophic at times, and carved a gorge through the moraine a mile (1.6 km) wide and 130 feet (~40 m) deep, which is now known as the Traverse Gap. While active, Glacial River Warren cut and eroded a bed up to five miles (8 km) wide and 250 feet (80 m) deep. This has left a valley which starts at Traverse Gap near Browns Valley, Minnesota, goes southeast to Mankato, then turns northeast to the Twin Cities.
...
Wikipedia