Lake Drain

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How glaciers melt and move is complex. Forced downhill by gravity, glaciers compress, deform, and slide, while moving and crushing the rocks beneath them. Every summer, lakes of meltwater form on the ice surface, and when the weight of the water becomes too great, the ice splits open to form channels that can drain the lakes in a matter of hours.

These supraglacial lake drainage events are significant, as they transport heat to the base of the ice sheet while lubricating the bedrock. It is hypothesized that this causes the ice sheet to accelerate its march to the ocean.

Early in summer, before efficient meltwater channels develop under the ice, meltwater at the bottom of glaciers can physically lift the entire mass of ice and move it downhill. As this water at the glaciers base rushes beneath a glacier, it slowly breaks down and dissolves rocks and even supports a diverse community of microbial life that lives beneath the ice. (Jack Cook, Woods Hole Oceanographic Institution)