The freshwater melting of Arctic ice, accumulated in lakes in Northern Canada (particularly Lake Agassiz), overflows and suddenly flows into the Atlantic Ocean (and/or Arctic Sea); the sudden decrease in salinity disrupts the marine currents in the North Atlantic and causes the brief glacial episode known as the Younger Dryas; some canyons (Ouimet, Boulders, Rabbit) in Canada remain as witnesses to this catastrophic event.
