Evaluating the Retreat, Stabilization, and Regrowth of Crane Glacier
against Marine Ice Cliff Process Models
The fastest projected rates of sea level rise appear in models which
include “the marine ice cliff instability (MICI),” a hypothesized but
mostly unobserved process defined by rapid, brittle failure of terminal
ice cliffs that outpaces viscous relaxation and ice-shelf formation. The
response of Crane Glacier to the Larsen B Ice Shelf collapse has been
invoked as observational evidence of this process, but limited data
coverage in space and time has limited our ability to meaningfully
refine our understanding of cliff failure processes using that event.
Updates to Crane’s subglacial topography show that much of its terminus
retreat occurred in floating, not grounded ice, but its retreat, arrest,
and regrowth over the last decade indicate brittle (not viscous)
processes dominated during the 2 years following ice shelf collapse. If
retreat occurred by cliff failure, maximum cliff heights would have been
111 m, consistent with process models that incorporate damaged ice.