During retreat of the Cassiar lobe of the Cordilleran ice sheet from the last glacial maximum there was a large stagnation or re-advance near what is now the north end of Lake Laberge (Lower Laberge) in the south central Yukon. This stagnation generated a large moraine that would come to act as a sediment dam for Glacial Lake Laberge. As the retreat of the ice front resumed a lake formed between the ice front to the south, and the sediment dam to the north. With the ice front continually drawing further south, combined with incision of an outlet flow into the sediment dam, the geomorphology of Glacial Lake Laberge constantly changed. Throughout the history of Glacial Lake Laberge there has been a gradual decline in the lake level largely controlled by incision into the sediment dam near Lower Laberge, as is indicated from sets of fluvial terraces above the current outlet river (the Yukon River). This gradual decline has produced several sets of preserved shorelines rising above the present lake level. By surveying the shape, location, and elevation of these shorelines and outwash terraces, in combination of all other applicable data sets, a detailed glacial retreat and alluvial history can be examined.