Ice mélange — sometimes known as sikussaq in Greenlandic — is that chaotic jumble of icebergs, bergy bits and sea water that sits in front of marine-terminating glaciers. It's been described as the world's largest granular material, and it's a characteristic feature of pretty much every calving glacier in Greenland. In winter, landfast sea ice forms and acts as a kind of seasonal glue, sticking the whole mass together. The question is: does this frozen-together mass actually hold the glacier back, like a tiny ice shelf? Or is it more like a pile of rubble that the glacier shoves ahead of it with barely any resistance? WE went into the field and dug through a huge amount of satellite data to find out....