How can refreezing water at a glacier’s base add mass to the glacier?

Refreezing water at a glacier’s base contributes to the glacier's mass by directly adding material to its underside, effectively increasing the overall size of the ice mass.1

While it was historically believed that basal water served primarily as a lubricating layer to facilitate movement across the ground, research has demonstrated that this water can refreeze, thereby accumulating mass at the base. This process also has the effect of lifting and altering the glacier's upper layers, a phenomenon that has been observed in various Antarctic ice fields, such as the Dome A plateau.1