It seems, Cryosphere Today made a mistake with their graph which has been amended to figures that show less ice disappearing.
Subject: [clim] Unprecedented Sea Ice Retreat Observed at Hudson Bay
Date: Tue, 10 May 2011 13:36:56 +0000
A near vertical fall of sea ice area graph results simply from thin ice film that is rapidly melting. The problem is that although ice area has been retained fairly well, the sea ice volume is not there to withstand sun's heat. The same problem will be seen later at the rear end of the Arctic Ocean where there is also very thin ice according to NSIDC. A perferct storm conditions ahead as far as one can see: http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.13.html