Shortly before Jakobshavn Isbræ, a tidewater glacier in Greenland, calves massive chunks of ice into the ocean, there's a sudden change in the slushy collection of icebergs floating along the glacier's terminus, according to a new paper led by the Cooperative Institute for Research in Environmental Sciences (CIRES) at CU Boulder. The work, published in Nature Geoscience, shows that a relaxation in the thick aggregate of icebergs floating at the glacier-ocean boundary occurs up to an hour before calving events. This finding may help scientists better understand future sea-level rise scenarios and could also help them predict when major episodes of calving are about to occur.