Paleogeography 13,400 years ago. Glacial Lake Iroquois is held back by an ice dam in northern New York. When that dam collapsed it drained (red arrows) into the lakes within the Champlain and Hudson Valleys, breaching the Narrows Dam (near New York City). It cascaded across the then exposed continental shelf to the North Atlantic Ocean. This release of meltwater reduced the flow of the Gulf Stream and caused an abrupt climate cooling in the Northern Hemisphere that lasted several hundred years. (Illustration by Jack Cook ©WHOI)
Paleogeography 13,300 years ago. Glacial Lake Candona forms in northern New York and southern Canada as the ice sheet retreats north.
Paleogeography 13,100 years ago. Glacial Lake Candona has expanded into the St Lawrence Lowlands as the ice sheet continues to retreat.
Paleogeography 13,000 years ago. Glacial Lake Candona drains into the North Atlantic through the St. Lawrence Valley as the ice sheet retreats from the region. The drainage of Glacial Lake Candona and the opening of the drainage out the St. Lawrence initiated another shut down of the Gulf Stream, causing the Younger Dryas cold interval.