I would also like to say that we should all remember that most of the processes (changes) that we are seeing today have been going on for many years now, but I (and many others) are concerned when this on-going processes result in fundamental change in future behavior, leading to sea level rise.
For example, the first image from Landsat in 2001 shows the same fracturing pattern in PIIS that Wipneus's post shows for 2014; however, the calving face has retreated back to the pinnacle that I referred to in my posts with crandles and should future local calving in the present day notch un-pin the many PIIS ice stream from the pinnacle then the calving face could retreat so far upstream that the SW tributary glacier ice flow accelerates and then reduces the stability of the Thwaites Glacier.
For another example, the second image from Landsat 7 from January 2013 (from
"A novel method for predicting fracture in floating ice" by: Liz LOGAN, Ginny CATANIA, Luc LAVIER, Eunseo CHOI; Journal of Glaciology, Vol. 59, No. 216, 2013, doi:10.3189/2013JoG12J210) shows that the crevasse cracking in the ungrounded Thwaites Glacier is on-going, but Google Earth images that I posted show that similar cracks were occurring for many years now. However, the Thwaites Ice Stream in this area is thinning rapidly and calving associated with the crevasse cracking that Logan et al 2013 discuss appear likely to accelerate in the future, especially, since most of the basal water existing from beneath Thwaites appears to be existing from this rapidly thinning area of ice stream.
Lastly, the third attached image of a computer model of warm water circulation in the ASE, supports that warm water does circulate underneath the area of the polyna that steve s refers to; but nevertheless, basal water leaking out from Thwaites would likely increase upwelling in this area; so who knows in any given year what processes does or doesn't clear-out the sea ice around the Thwaites Ice Shelve at any given time of year; I guess we will all have to watch and see how the patterns/processes change with time; but I am very concerned that during an El Nino event that the warm water circulation in and around both the PIG and the Thwaites Glaciers will accelerate grounding line retreat and ice mass loss.