(C) Daily Kos This story was originally published by Daily Kos and is unaltered. . . . . . . . . . . Greenland will make the news someday, but that day is not today - Winter flood under the ice. [1] ['This Content Is Not Subject To Review Daily Kos Staff Prior To Publication.', 'Backgroundurl Avatar_Large', 'Nickname', 'Joined', 'Created_At', 'Story Count', 'N_Stories', 'Comment Count', 'N_Comments', 'Popular Tags'] Date: 2023-03-06 One of many massive melt water lakes in Greenland. Greenland glaciologists observed a surface lake of meltwater drains away in the middle of winter for the first time. Meltwater covers the icecap in the summer from surface warming. The meltwater forms rivers, streams, and tributaries that will either create a lake (known as a supra lake in glaciology jargon) resting on the surface or plunge to the bedrock via a hole in the surface known as a moulin. The surface water refreezes in winter in a yearly cycle observed since satellite ice imagery began in the 1970s. Or, at least, it used to. Once winter arrives and heavy snowfall occurs, covering these, sometimes enormous lakes, they become insulated from the cold and remain a viscous liquid through the bitter cold of winter. By examining a large dataset, researchers from France, Denmark, and the United States found that a fifty-year-old glacial surface lake in western Greenland burst through a fracture and flooded the Jakobshavn Glacier below, draining the water directly into the ocean. This lake collapse occurred upstream of the Illusiatt glacier, the most dynamic glacier on earth. Camille Lin writes in Polar Journal. On March 9, 2018, upstream of Ilulissat 142 kilometers inland, and at an altitude of 1,600 meters on the Jakobshavn Isbræ cap, two glacial lakes disappear. “A fracture opened up and a conduit formed below the surface of the glacier,” says the glaciologist. This event triggers an acceleration of the glacier’s downstream flow. “This is the first time that such a high flow velocity has been observed in winter. The passage of the flood has changed the physical constraints between the ground and the glacier, and other lakes have also drained downstream, a cascade effect,” he adds. The water was able to lift the hundreds of meters thick glacier by 20 cm. Now, whether glacier flow will tend to accelerate due to subglacial flooding remains a matter of debate in the scientific community. “There are two schools of thought”, discusses the glaciologist. “One is that the acceleration of glacier flow will not occur because the water is cutting channels underneath them. The other thinks that crevasse fields may rise in elevation allowing meltwater to find the glacier bases further upstream, and would accelerate the flow of the upstream part of the glaciers.” Eventually the two schools could come together. “They may agree,” he concludes, “that the glaciers will flow faster at higher elevations, and then downstream they would flow slower, but melt all the more.” On the whole of the coastal glaciers of Greenland, the researchers located 4 other drainages of this type. “The one in 2018 represents a sea level rise of 0.0005 mm,” he calculates. That’s not much, but it shows that there is a lag of several decades for this water to reach the sea.” Information to consider when predicting sea level rise. x Taking the NYC 🇺🇸 Subway 🚇 in 2050 👇👇👇 Via @ClimateAdpic.twitter.com/y0x3uHluie — Daniel Moser - dmoser@mastodon.social (@_dmoser) February 17, 2023 Perhaps a similar but more significant drainage event is why Disko Bay’s icebergs are no longer present—just a hunch on my part. Maybe it could be named a meltwater pulse. The article did not say. Where is the media? [END] --- [1] Url: https://www.dailykos.com/stories/2023/3/6/2156507/-Greenland-will-make-the-news-someday-but-that-day-is-not-today-Winter-flood-under-the-ice Published and (C) by Daily Kos Content appears here under this condition or license: Site content may be used for any purpose without permission unless otherwise specified. via Magical.Fish Gopher News Feeds: gopher://magical.fish/1/feeds/news/dailykos/