JayW, it fits into the 'heatwave' that will last up to next Sunday in the Western Archipelago.
2012G seems to be as far North as Borden Island, big lead filled with rubble opening up there, right into the CAB.
Almost +10dC might be a bit unlikely though. Climate Reanalyzer has lower temps over the ice; about +1-+3.
Nevertheless, the channels are taking a beating. Mould Bay, Pr. Patrick Island, has several days on +5-+7, Melville Island will go over +10dC.
Wonder if Pr. of Wales Strait (Banks-Victoria) will start breaking up soon.