Besides Gerontocrat's chart, it is worth noting that flux beyond the raw positives is also increasing, and this measure is less visible (i.e. more snow and melt superimposed on the already dramatic increase, canceled out each day).
While the snow melt is significant, so is the prolonging of winter into April, May, and June. This does not mean melt stops when it normally starts and then commences later, the flux component means that melting still starts roughly when it used to, but it can keep going for much longer and peak much later in the year.
This makes the relative impact to temperatures much more significant than it would otherwise, IMO. The other factor is that the albedo differential in spring results in colder airmasses drifting into the NW NATL, activating ++sea ice in Newfoundland and Labrador vicinity and pushing cold winds atop the already-cold waters driven by the SWE flux.
Greenland can certainly contribute as well but even as bold as this year's melt has been, it hasn't held a candle to 2011-12 (despite overall albedo in Greenland appearing about as bad).
I think eventually this blob is going to persist late enough into the summer along with ++sea ice in Hudson Bay and +++SWE in Canada that we could see sustaining feedbacks continue past July, which would result in accumulations all-year-round for practical purposes.
Another interesting feature in 2019 is the cold blob that emerges from the West Coast from April into July. Thanks to the epic snow melt. These meltwater blobs are only two among many and are superimposed atop an overall regime of otherwise incredible warmth.