How does frost wedging fracture an ice shelf?

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iceberg Tourist boat in front of a massive iceberg near the coast of Greenland.

Frost wedging contributes to the fracturing of an ice shelf through a process involving surface meltwater. During warmer periods, meltwater accumulates on the upper surface of the ice shelf and flows into existing crevasses. As temperatures drop, this liquid water refreezes within the cracks. Because water expands as it turns into ice, this refreezing process exerts significant pressure at the base of the crevasses, effectively acting as a wedge that forces the cracks to deepen and widen. This mechanism causes the ice shelf to splinter in multiple locations, ultimately leading to its disintegration and the calving of icebergs.1