Another scenario for a complete meltdown is imo strongly related to the cracks. Last year a large anomoly showed up in Mackenzie bay, at its most extreme IIRC there were 12 bands each indicating 2deg. implying 24deg.C on the actual temperature map. This was the implied temperature of the ocean closest to the shore, although it wasn't sustained at this level for more than a few days the anomoly persisted past the date of the max. The only other feature that showed any similarity to this was the anomoly on the western shore of greenland, it wasn't so extreme but it too had a gradient, was warmest by the coast and isolated from any similarly warm water.This seems to be best explained by the restratification of waters by eddy kinetic energy, caused by the currents returning north having traversed the east coast of greenland. A number of papers are available search EKE, eddy kinetic energy, labrador sea, I've previously linked a couple on ASIB.
The only likely supply of kinetic energy to effect the anomoly in Mackenzie bay is the Pacific. Looking at the tidal ranges at Point Barrow and Tin City
http://www.americantides.com/ It's clear that Arctic tides [.4m] have about a third the range of the Pacific [1.1m] ones in this area, implying that whenever high tides occur in the north Pacific an extended pulse of Pacific water will enter the arctic. If you look further south in Alaska
http://www.americantides.com/tide-predictions/black-rock-walrus-islands-alaska where the range is more than 4m some sense of the inertia in this dynamic can be grasped.
My contention is that once this "Pacific" water passes through the strait, it is lost to the pacific due to the diference in rotational speed between its origin and where it now finds itself. Going from 60N to 75N effectively halves the distance to the rotational axis and the local speed of the earths surface, a large fraction of that energy is posessed by the inflowing water which would be more energetically comfortable further south, but is compelled eastwards by the excess of kinetic energy carried with it through the strait.
Although this is the warmest/least saline of Pacific water it is nevertheless denser than the ice/fresh water floating atop the Arctic ocean and consequently dives below it. My guess is that before 2007 what it found there was an endless inverted landscape of ponds and small freshwater lakes formed by the mechanically impacted ice, and whatever damage/melt it caused was confined to these or merely spilled into the next [inverted] pond, and should this fresh water spill over and reach the surface that too was largely contained within the arctic by the extensive permanent ice, like an inverted freshwater sea contained by an ice mountain range. Ready for the next freeze.It may have happened before but I think there was a breakthrough for that fresher water towards the end of July last year.
You'll have to form your own impression of the action of EKE but my veiw is that as it rolls like a tidal wave across the inverted landscape, the 'surf' before it is the heat both of its own motion and that carried to the surface from the warm saline Atlantic waters at depth, and just like a wave when it meets an obstacle it waits until the trough is filled or the barrier overcome before proceeding. Thus wherever a gap appears in the ice warm water will be brought to the surface and wherever the ice changes thickness a similar build up will enhance the probability of cracks forming as the wave swells before moving on. In time however the landscape will erode to a much leveller plane. Whilst this process has been happening since at latest 2007 I think the cracking this year indicates a more 'mature' inverted landscape beneath the ice, and the likelyhood of all the bottom/meltwater with nowhere to hide, being shunted out of Fram or through the archipelago by the energetically charged influx coming twice a day from the Pacific.
All the above is compounded by the fact that last year over vast areas the air temps were too high for ice to form but cold enough for snow to settle, yet it appeared this snow was being counted as ice in some of the models, well over the winter no doubt some of it became ice of sorts, probably the sort easily melted by increasingly unimpeded Pacific water on its way to Fram/Baffin.
Just two last points, prior to 2007 I'm sure the kinetic energy was expended before it reached across the arctic, after the breakthrough I expect the flow slowly accelerated, just as it will this year, if theres anything at all in this, and as it does the ice disappears never mind the weather.
If this is indeed what's happening, and i think it is even though what evidence i see is somewhat ambiguous, we need a north wind through Bering because without it the fresh water lens will disappear south leaving nothing for the Atlantic water to dive beneath and consequently nothing to stop the sudden evacuation of the extreme saline basal waters through Frams basement etc.etc.