Flow of the Western Antarctic Ice Sheet is distinctly heterogeneous in a vast region bordering the Ross Sea. Broad streaks of ice, ~1 km thick, called "ice streams", having horizontal width of several 10s of km, slide over their bed (of soil-like matter, which was seafloor in the last inter-glacial period) at > 100 m/yr, whereas they are bordered laterally by stagnant ridges flowing at < 10 m/yr. Major issues are those of why this morphology forms and what it means for the overall rate of ice loss. Our recent studies show how shear heating of the ice, consequent formation of temperate ice zones producing melt as they deform, and subglacial hydrological processes associated with Rothlisberger drainage channels, can naturally form a non-singular Barenblatt ending of a tens of km long shear crack between ice and till at the bed.
