Lake Agassiz

During the last ice age, a 700-mile long by 200-mile wide lake centered on the province of Manitoba covered central Canada, dammed by glacial ice.

Named Glacial Lake Agassiz, for the famous Swiss scientist and later Harvard professor Louis Agassiz, who was among the first to recognize landforms that indicated that vast continental ice sheets once covered the continents, the lake drained catastrophically when the ice dam collapsed.

Water tied up in glaciers and in glacial lakes during the last ice age caused sea-level to drop more than 100 meters. At its maximum extent, Glacial Lake Agassiz was the largest body of fresh water on the planet, and held more water than all the worlds lakes today. When the climate warmed and the ice dam was breeched, the resulting flood raised global sea levels by half a meter.

More info: http://www.cloudnet.com/~edrbsass/agassiz.htm

Source: Perkins, Sid, Once Upon a Lake, Science News November 2, 2002 v. 162:p. 283

Illustration credit: Maximum extent of Glacial Lake Agassiz,

http://mrbdc.mnsu.edu/mnbasin/fact_sheets/valley_formation.html