The great continental ice sheets were melting very fast in the time of Glacial Lake Missoula, shedding great torrents of meltwater every summer, raising sea level an average of approximately 100 ...

The glacier, a southern tongue of the great Cordilleran ice sheet that ... arrived inside icebergs caught in a Glacial Lake Missoula flood. When the bergs grounded and melted here, the rocks ...