Lake Agassiz, which existed roughly between 13-8.5k years ago in the area now including Manitoba, Saskatchewan, North Dakota and Minnesota, was a glacial lake (a lake formed by leftover melting ice which collects during the retreat of a large glacier) of truly immense proportions. Major drainage events were likely due to the hot periods several thousand years ago which caused ice and glaciation blocking the sides of the lake to melt, thus allowing the lake waters to flow freely. Such drainage events were so massive that it is hypothesized that they may have had easily measurable effects on planetary climate, including ocean circulation disruption and disruption of weather patterns due to the sudden oceanic influx of cold water. The final drainage at the end of the last ice age was so massive that it may have contributed to a global rise in sea levels of up to 3 fucking meters. The lake was estimated to cover more surface area than all the Great Lakes combined, and to contain more water than all the lakes on the planet put together.