Missoula floods

Glacial Lake Columbia was the lake formed on the ice-dammed Columbia River behind the Okanogan lobe of the Cordilleran Ice Sheet when the lobe covered 500 square miles (1,300 km²) of the Waterville Plateau west of Grand Coulee in central Washington state during the Wisconsin glaciation.^[1] Lake Columbia was a substantially larger version of the modern-day lake behind the Grand Coulee Dam. Lake Columbia's overflow – the diverted Columbia River – drained first through Foster Coulee, and as the ice dam grew, through first Moses Coulee, and finally, the Grand Coulee.^[2][3]

• https://en.wikipedia.org/wiki/Glacial_Lake_Columbia
• https://www.google.com/maps/d/u/0/viewer?mid=14YY3J0HLMehpL22SVtE7LYReVC80PyxR&hl=en&ll=47.76398982714841%2C-119.17411259240176&z=13