It took almost a month for meltwater to accumulate atop Greenland’s ice sheet in the summer of 2006. It took only
90 minutes for all that water — a lake so large it could fill New Orleans’ Superdome more than 12 times
over — to pour through a crack in the kilometer-thick ice below it and drain
the lake dry.
At its height, the torrent exceeded that of Niagara Falls, and its rumbling triggered
seismic instruments nearby. GPS equipment indicated that the westward flow of
ice in the region briefly surged, a sign that the water drained down to the
bedrock and temporarily lubricated the boundary between ice and rock.