Fracture propagation as means of rapidly transferring surface meltwater to the base of glaciers

Abstract

Propagation of water‐filled crevasses through glaciers is investigated based on the linear elastic fracture mechanics approach. A crevasse will penetrate to the depth where the stress intensity factor at the crevasse tip equals the fracture toughness of glacier ice. A crevasse subjected to inflow of water will continue to propagate downward with the propagation speed controlled primarily by the rate of water injection. While the far‐field tensile stress and fracture toughness determine where crevasses can form, once initiated, the rate of water‐driven crevasse propagation is nearly independent of these two parameters. Thus, rapid transfer of surface meltwater to the bed of a cold glacier requires abundant ponding at the surface to initiate and sustain full thickness fracturing before refreezing occurs.