Researchers Finally Solve the Mystery Behind the Ghostly Mitten-Shaped Structure on Greenland Ice

The sudden appearance of a ghostly dent in one of the ice sheets of Greenland left scientists concerned about the mystery behind it. The apparent depression, shaped like a mitten glove, in the Flade Isblink ice cap was spotted in satellite images after a subglacial lake collapsed beneath the snowy surface in 2011. To solve the riddle of the giant spooky figure about 2 miles long and 1 mile wide, researchers conducted field observations and devised theories to explain the phenomenon. According to NASA’s Earth Observatory, the depth of the feature was recorded at 230 feet during its initial formation but has since risen by several feet. 

A 2015 study published in Nature Journal explained that the subglacial lake located just below the ghostly figure had rapidly drained out of water into a nearby fjord, with a peak estimate of 7,600 cubic feet of water escaping every second, resulting in an underground cavity. Researchers were not privy to the collapse right away as the area happened to be masked by clouds in the satellite imagery. The glove-like formation is said to have formed between August 16 and September 6, 2011. 

“Serendipity in science is important. I wasn’t looking for this feature, and it was a surprise to see it,” said lead author Michael Willis, a glaciologist at Cornell University. The submerged lakes are formed when meltwater from the surface finds channels to seep deep down into the ice cap, the bedrock, and the ocean. A follow-up study in 2022 found that the drained lake had been refilling since 2012 as the floor of the cavity had risen to 50 feet below the surrounding ice and 180 feet above. 

While scientists deciphered the cause behind the mitten-shaped depression in the ice cap, they were unable to explain the accelerated drainage in 2011, speculating that climate change caused by human activity may have contributed to the icy apparition. With increasing global climates, scientists are wary that more ice meltwater will facilitate further ice loss risking the stability of subglacial lakes. 

Kelly Brunt, a glaciologist at NASA’s Cryospheric Sciences Laboratory not involved with the study, talked to NASA and marked the natural event as the “first recorded instance of a rapid drainage of a subglacial lake in Greenland.” She noted that there are several other subglacial lakes in Greenland but their predominantly stable nature eliminates the risk of similar collapses. Besides the effect on subglacial lakes embedded into the thick ice sheets of Greenland, ice melting is part of the larger problem of rising sea levels.

According to another report by NASA, the polar regions are losing ice mass at record rates, about 150 billion tons per year in Antarctica and 270 billion tons per year in Greenland since 2002. The ice sheets constitute about two-thirds of all the fresh water on the planet, and ice meltwater has contributed to one-third of the global average rise in sea level since 1993. The GRACE Follow-On mission, a follow-up of NASA’s GRACE, collected data monitoring both the ice sheets since June 2018. Located in the Arctic, Greenland has an ice coverage three times the size of the US state of Texas and a mile deep on average, per JPL NASA. Therefore, it is not difficult to imagine the dramatic consequences if and when most of the ice in the region is converted into meltwater.