We have a new paper out in the Journal of Glaciology led by our colleagues in the Stanford Icy Physics Lab demonstrating that the presence of firn on ice sheets imparts significant resilience to hydrofracture. We used a poromechanical model to show that when water drains through fractures in Greenland’s ice slabs, most of the hydrostatic stress at the fracture tip is accommodated by a change in pore pressure, rather than being transmitted to the solid skeleton. As a result, fracture propagation arrests and water leaks off into the firn, reducing runoff from the ice sheet and preventing the formation of surface-to-bed hydrologic connections that can modulate ice velocity. Read more here.