Collapse of marine-based outlet glaciers from the Scandinavian Ice Sheet

► Younger Dryas outlet glaciers in fjords in Western Norway were >2000 m thick. ► They retreated 240-340 m/year during the 500 years period 11.6-11.1 ka BP. ► Net retreat from LGM to the Ice Divide occurred in two steps 7000 years apart. ► The first step was calving of the Norwegian Channel Ice Stream 19.5-18.5 ka BP. ► The second step was the break up of fjords 11.6-11.1 ka BP.