The end of Kaldalonsjokull

 

Above: a new (Sept 2022) photo of Kaldalonsjokull, the glacier that I saw for the first time in 1960. Below: a photo which is not dated, but I think it might be from around 2016.  At that time it looked as if the glacier was in poor health, with a single large ice stream tumbling down an icefall (as I remember it) now replaced by two smaller segments of active ice, separated by a patch of thin and apparently dead ice close to the trough head.  About six years later, the trough head is clearly exposed, and it looks as if the ice supply from the left branch is also being cut off.  The Drangajokull ice cap is clearly thinning dramatically, and I suspect that in around ten years time -- since the rate of wastage is accelerating -- no ice at all will be reaching the Kaldalon trough.......

The bottom photo shows the glacier in the early summer, when thick seasonal snow blanks out the glacier surface at the head of the trough.

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https://www.researchgate.net/publication/277563619

A 300-year surge history of the Drangajokull ice cap, northwest Iceland, and its maximum during the 'Little Ice Age"

Skafti Brynjólfsson, Anders Schomacker, Esther Ruth Guðmundsdóttir and Ólafur Ingólfsson

The Holocene, Vol. 25(7) 1076–1092

June 2015

DOI: 10.1177/0959683615576232

Note that the Kaldalon glacier has not just retreated steadily over historic time.  It is a periodically surging glacier, as seen on this diagram from Brynjolfsson et al 2015.  The seven "surge moraines" seen in the valley (only some of which we noticed in 1960!) represent short-lived glacial advances;  these occur irregularly, when conditions are right.  The biggest surge since 1740 occurred between 1994 and 1999, when the glacier advanced about 1 km, down the steep trough head slope.  These are the periodic interruptions in an overall rather catastrophic retreat.  The glacier has thinned by about 250m since 1740.  When we were in Kaldalon in 1960, the glacier edge was down on the flatter valley floor.  In 1994 the snout was high up on the headwall, but then the last surge brought the snout down to approx the 1960 position again.  Since then, retreat has been even more catastrophic, as we can see from the photo at the head of this post.

There is further information in this article:

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/6C06AD0F2DC7B5A210779F5844BFAF79/S0260305500260606a.pdf/ice-volume-changes-bias-estimation-of-mass-balance-measurements-and-changes-in-subglacial-lakes-derived-by-lidar-mapping-of-the-surface-of-icelandic-glaciers.pdf

An extensive area to the NW of the Kaldalon glacier outlet has now become so thin that bedrock shows through occasionally, and it should be treated as a semi-detaches snowfield.  During the surge of 1995 - 2005 Kaldalon Glacier advanced and thickened by about 85m, while in parts of the catchment to the north the ice surface sank by more than 20m.