Timothy A, thanks for getting the Jakobshavn forum back on track. On these fast-breaking events, the initial flash commentary naturally gets some things right and some things wrong; with the internet, both persist. Later commentators may see more of the latter than the former and inadvertently add more sand to the castle.
In the dark of winter, when satellites can't see anything in the visible, it is imperative to review what exactly they are sensing and how that proxy is interpreted and processed into a visible image product. For example, just a very subtle break in the color palette centered around a salinity freshening event can create a dramatic illusion of bulk transport, movement that didn't actually occur.
In my view, this was strictly an event within the realm of physical oceanography. Andreas Muenchow is the only forum member with demonstrated competency in that discipline (44 papers cited 1041 times) so even his preliminary comments should be given great weight.
Jason Box has not published in this field but has many important papers on the land side, notably
http://tinyurl.com/jcsf6u7 on the 2012 runoff. See also
https://www.researchgate.net/profile/Jason_Box/publications for his 170 papers and respectable cite count (over 69% of mine but surprisingly only 33% of E Rignot's). Rignot's group produced the critical channel bathymetry data that Andreas M would need for oceanographic modeling.
To summarize, there is no observational evidence at this time in support of a noteworthy discharge of fresh water or sediment from under the Jakobshavn ice stream. Instead the hurricane remnants merely blew the melange out of the fjords, overturning a lot of water in the process, making this a twofold experimental gift:
-- how big are the hiccups in ice stream velocity when buttressing is suddenly removed at various glaciers?
-- how much mixing of surface (PW) with deeper (denser warmer AW) waters came about?
We could pursue the first of these with Sentinel 10 m but so far no one has done that. For the latter, re-read the three recent papers from the Holland group and await further word from Andreas M. He has access to better oceanographic products, the experience in interpreting them, and the capacity to run oceanographic models.
A central issue with Jakobshavn-meets-the-ocean is the sill at the far western end of the fjord. It is too high to allow much AW waters in. However the sill has a gap in the NE whose height is still uncertain.The other issue is churning of otherwise stably stratified waters at the face of the calving front. That comes about from basal meltwater jets, calving processes themselves, and potentially here, high winds from the east.
http://efdl.cims.nyu.edu/publications/refereed/jpo_jig_part_1_2015.pdfhttp://tinyurl.com/hapq9p5 part II
http://www.the-cryosphere-discuss.net/9/4583/2015/tcd-9-4583-2015.pdfhttp://www.nature.com/ngeo/journal/v1/n10/full/ngeo316.htmlThe hurricane might have brought rain; western Greenland is peppered with AWS weather stations but it seems no one has checked them. The Illulisat airport would surely have excellent records too (Jim H is on this above). Heavy rain at the 1500 m contour or above would be quite remarkable any time of year, unprecedented for mid-January.
I'm inclined to think it didn't happen. The weather brought with the hurricane was not warm enough long enough to produce significant basal meltwater given the low heat capacity of air and its poor thermodynamic coupling with ice surface compared to rain that freezes. The big rain event in late August 2012 had very dramatic effects on the land-terminating glaciers to the south, with instructive subsequent journal papers discussed here many times before.
However future rain, especially farther up and farther north, is a huge (and largely imponderable) consideration for western Greenland's future contribution to sea level rise. In terms of ASLR's risk analysis, unforeseen rain on ice is yet another reason to apply the precautionary principle to activities that contribute to further climate change.
