 Coastal alpine glaciers started to retreat around 19,000 cal years BP  while Cordilleran ice continued advancing in the Puget lowlands up to 14,000 14C years BP (16,800 cal years BP).Even during the maximum extent of coastal ice, unglaciated refugia persisted on present-day islands, that supported terrestrial and marine mammals.As deglaciation occurred, refugia expanded until the coast became ice-free by 15,000 cal years BP.