Greenland lake disappears under the ice
This report via Ars Technica about glacial lake draining is amazing:
A report in today's Science describes how researchers recorded the drainage of one such lake in Greenland. The lake was roughly 5.6 km2, but drained completely in less than an hour and a half. The lake's contents rapidly made their way down to the bottom of the ice sheet, 980 m below the surface. During this period, the average drainage rate was 8700 m3/s. For reference, the average flow rate for Niagara Falls is only 5700 m3/s.