Basal Sliding Basal sliding, the second way ice moves, can happen several different ways. True basal sliding means that the base of the ice sheet is near the pressure melting point, and that some water is present. The pressure melting point is reached because high pressure actually reduces the temperature at which ice will melt. The thicker the ice, the lower the temperature at which it will melt, and the higher the chance that some water will be available at the glacier base to enhance movement. Large parts of the West Antarctic Ice Sheet are at the basal melting point, so there may be large areas under the ice sheet where a thin water layer exists.
Water reduces friction, and allows the ice to move faster.
A thin layer of water may be present at the glacier base because the ice is at the pressure melting point. Or, the water may come from rain water or surface meltwater that has worked through the cracks in the ice. Or, it may originate from melting upstream in the glacier. Movement by basal sliding is ten time faster than movement by internal deformation . Basal sliding is extremely important in how much a glacier erodes the landscape, and the features that are created by the ice.