What a coincidence. Yesterday I wrote in a comment:
There's a fantastic segment on the Arctic Sea Ice Forum for discussing Greenland and its glaciers, with people presenting all kinds of analysis and satellite images. Really top quality stuff.
Well, the folks there (forum member Espen Olsen to be precise) have spotted a large change in Jakobshavn Isbræ, Greenland's fastest glacier draining 6.5 % of the Greenland ice sheet, between August 14th and 16th:
Espen reckons this is one of the largest calvings in many years, if not the largest. It also means that last year's retreat line has been passed now (date should be Aug 16 2015):
I'll update this blog post as more becomes known about this calving event, especially the size of the calving. In the meantime, here's an image showing the previous retreat lines through the years, found in this blog post on the Great White Con blog that described another big calving event earlier this year in February:
As Great White Con blogger Jim Hunt wrote at the time:
This most recent event does not bring the calving face further east than the position in summer 2014. However the sun’s rays are only just returning to that part of the planet, and the next one may well do so.
Well, there you have it, Jim. It's there.
It is estimated over on the Forum that the total area of ice that has calved off Jakobshavn Glacier measures 12.5 km2, as compared to the estimated 7 km2 back in February and another 7 km2 back in 2010 (according to NASA). This image made by forum member A-Team shows the area:
Update August 19th:
There's a great article up on the Washington Post website linking to this ASIB blog post, with reactions from glacier experts like Richard Alley, Jason Box and Eric Rignot.
Update August 20th:
NASA's Earth Observatory website also has an article up, accompanied by a fantastic image comparison tool. I want it.