possibile the currents in the arctic have basically reversed? Could the whole pack drift all the way to Russia? similar detachments in previous years?
A freely floating ice pack, just blowing in the wind (not so much by currents), has not been raised often as a concern because winds have held it against the CAA where temperatures are colder and winter thickening more dependable.
The weather pattern broke down in early June 2018 and no consistent anti-cyclonic ice movement has been seen since. This can be seen in the chaotic sequence of daily motion vectors at OSI-SAF.
http://osisaf.met.no/p/osisaf_hlprod_qlook.php?year=2018&month=02&day=09&action=Today&prod=LR-Drift&area=NH&size=100%25To repeat once more, we are not much concerned with air pressure per se, which though an important driver of event is merely a weak upstream proxy. It is ice movement at the end of the day that matters, as shown on Ascat or tracked daily at OSI-SAF. And that depends on many other factors other than pressure contours and gradients, such as sails and sea anchors (pressure ridges and underwater keels).
A freely floating ice pack would be a "major development" because the ice pack could drift off into warmer waters or break up into several smaller pieces, both of which exacerbate ice volume and extent loss.
I don't recall seeing detachments quite like this before, it is easy enough to check August back to 2012: no two years are alike, Augusts are not always comparable, some detachments can be seen. The animation rows, top to bottom, are 17-16, 15-14,13-12.
Note the main Northwest Passage isn't going to open up at this rate because M'Clure Strait is constantly being stuffed with CAB ice. A roundabout passage may open up on a few days however.
Below, a new version of Oct 15-May 30 Ascat of ice motion in and along the CAA. Lateral detachment, corks bobbing, blocks tumbling, lift-offs and immense lead fracturing etc can be seen. As FishOut notes below, the thick landfast ice is gone; the ice now is extremely mobile just off shore, with big blocks tumbling end over end this year and MYI thinning in extent and even disappearing entirely.
So yes, things may be moving to
WIPD (whole ice pack detachment) en route to a BOE (blue ocean event) but WIPD competes with more certain trends such as overall area or volume loss that could precede or moot it.
Or not: the png at bottom shows what remains to happen to achieve total detachment (taken as a path around the entire ice pack of open water to <20% concentration). Even if the ice does hit WIPD this month, without winds moving the pack well offshore, it will simply freeze back onto land in October. Note though the CAA continental shelf is very narrow so it wouldn't take much to create an apron of FYI around the entire pack perimeter.