More than the usual summer melting

In a typical summer about half of the ice sheet in Greenland melts.  Summer 2012 is quite different.  In four days from July 8 to 12 melting of the surface went from 40% to about 97%. How  much of the entire glacier melted is not known.  Nor is it known whether this extensive melt event will affect the overall volume of ice loss this summer and contribute to sea level rise.  This phenomenon has occurred before, 1889 being the most recent.

There is a great video of the collapse at the BBC site, which did not allow sharing.  Click here to view it.

NASA has some shots also.  Here is what things looked like on July 8.

After the melting this is what it looked like on July 12.