Researchers have discovered craters left behind when two lakes under the Greenland ice sheet rapidly drained recently — an indication
that a massive amount of meltwater has started overflowing the ice sheet’s natural plumbing and is causing “blowouts” that drain lakes away, they say. One of the two lakes once held billions of gallons of water and emptied to form a mile-wide crater in just a few weeks, researchers report in the journal The Cryosphere. The other lake, described this week in the journal Nature, was two miles wide and has filled and emptied twice in the last two years. The researchers suspect that as more meltwater reaches the base of the ice sheet, natural drainage tunnels along the Greenland coast are cutting further inland. The tunnels carry heat and water to areas that were once frozen to the bedrock, potentially causing the ice to melt even faster.
Crater left after a Greenland lake drained.