Some of the largest floods in earth history ... and occurred when the Cordilleran Ice Sheet (CIS) was near its maximum extent. At this time, the Okanogan Lobe and Purcell Trench Lobe blocked the ...

When Glacial Lake Missoula's ice dam shattered, a northern arm of the ... that took place along this portion of the gap as the flood pounded through. 2. Mission Mountains One of the most striking ...