New LiDAR data covering the Southern Fraser Plateau in British Columbia revealed a number of landforms associated with large-scale flooding, including dry cataracts, spillways, and large-scale bars. Additionally, a variety of paleo-lake indicators have been identified upflow of these flood-related landforms; in combination these landforms suggest three proglacial lake outburst floods (GLOFs) along the retreating southern margin of the Cordilleran Ice Sheet during deglaciation in the region. Ground observations in the study area confirmed the existence of characteristic flood landforms. Three different dry cataracts cut into Chilcotin group basalt range in height from 10 to 50 m, each with a plunge pool at the base and an extensive tract of angular boulders extending downflow. Upflow from one cataract, the landscape is extensively scoured and exhibits s-forms and a boulder lag. Downflow from the same cataract, longitudinal grooves (150 m long, 20 m wide, 2-3 m deep) are cut into bedrock. From ground penetrating radar and sedimentology data, two adjacent flood bars downflow from the same cataract are deposited atop an irregular bedrock surface and are composed of a 3-m thick inversely graded bed of granules up to meter-sized boulders overlain by a 3-m thick unit of poorly sorted, massive sand and gravel. Both units have ab-plane clast fabrics flow transverse as inferred from the geomorphology of the channels around them. Our results support high magnitude GLOFs from breaches of ice dams retaining the proglacial lake. Each GLOF resulted in large changes in the depth (10’s m decrease in elevation) and extent (order of magnitude increase in area) of the proglacial lake and ice margin position (10’s km retreat) prior to drainage through a lower elevation spillway. This relationship suggests that a portion of deglaciation in this region was largely controlled by the growth and draining of large proglacial lakes, which has implications for modern glaciers and ice sheets with ever growing proglacial lakes in the face of global climate change.