Data from: Undercutting of marine-terminating glaciers in West Greenland

Marine-terminating glaciers control most of Greenland’s ice discharge into
the ocean, but little is known about the geometry of their
frontal regions. Here we use side-looking, multibeam echo
sounding observations to reveal that their frontal ice cliffs are
grounded deeper below sea level than previously measured and
their ice faces are neither vertical nor smooth but often undercut by the
ocean and rough. Deep glacier grounding enables contact with
subsurface, warm, salty Atlantic waters (AW) which melts ice at
rates of meters per day. We detect cavities undercutting the base of the
calving faces at the sites of subglacial water (SGW) discharge
predicted by a hydrological model. The observed pattern of
undercutting is consistent with numerical simulations of ice melt
in which buoyant plumes of SGW transport warm AW to the ice
faces. Glacier undercutting likely enhances iceberg calving, impacting ice
front stability and, in turn, the glacier mass balance.