sliding

Two mechanisms operate to permit sliding over a rough bed. First, small protuberances on the bed cause stress concentrations in the ice, an increased amount of plastic flow, and ice streams around the protuberances. Second, ice on the upstream side of protuberances is subjected to higher pressure, which lowers the…

…pressures produce high rates of sliding. Normal temperate glaciers ending on land generally have subglacial water pressures in the range of 50 to 80 percent of the ice pressure, but glaciers that end in the sea may have subglacial water pressures almost equal to the ice pressure—that is, they almost…