The Franklin Glacier Complex was covered by the Cordilleran Ice Sheet until its retreat about 13,000 years ago. Franklin Glacier has since undergone glacial retreat and expansion throughout the Holocene. It appears to have retreated significantly during the early Holocene warm period, followed by advancements 6,300, 5,400, 4,600, 4,100, 3,100, 2,400, 1,500, 800 and 600 years ago. The timing of expansions corresponded with cool summer temperatures, generally moist conditions and increased precipitation.