Kaldalonsjökull -- portrait of a dying glacier

When we worked on this glacier in 1960 the snout was located in the foreground of the photo.  In 65 years there has been a phenomenal retreat of over 1 km, exposing the rocky knolls to the right and the spectacular rock bench or ledge that we see in the centre of the image.  However, this retreat from the 1940 surge position was disrupted by the most recent surge between 1995 and 1999, which involved a readvance of 1015m.  Over the past 25 years there has been a continuous retreat of the ice edge.

I have just come across this fascinating photo collection, with recent photosn of the snout of the Kaldalonsjökull -- one of the small outlet glaciers associated with the Drangajokull ice cap in NW Iceland.

https://icelandthebeautiful.com/kaldalonsjokull-drangajokull-strandir-vestfirdir-island/#:~:text=Kaldal%C3%B3nsj%C3%B6kull%20is%20a%20glacier%20tongue,falling%20rocks%2C%20so%20be%20cautious.

With colleagues, I worked on this glacier in 1960 and 1973-74, when it was quite active, covering virtually all of the rock exposures seen in the above photo:

Kaldalonsjokull snout, 1960.

The current snout, which is nothing more than a patch of dead ice detatched from the main ice cap.  The trough head cliff at the top of the photo is a prominent feature.

Another view of the present-day wasting glacier, with just one current connection to the ice cap, on the extreme right of the image.

The evolving situation

The 2006 satellite image.  The position of the rock ledge is shown by the snow banked up against the cliffline.  In the 1970's the rock ledge was occasionally exposed but mostly snow-covered.

Left image: 1960 aerial photo. Right image: 2025 satellite image. there has been an overall retreat of over 1 km.  However, in the period between 1960 and 2025 there has been another surge which pushed the ice front back to approximately its 1960 position, leading to a somewhat confusing situation in the current ice wastage zone........

View of the upper part of the glacier, seen from the adjacent Votubjorg basalt plateau, 1975.  This is the position of the trough head or bench, with a readily identifiable cliff edge and an extensive platform with fluted till and a scatter of boulders above it.  Since 1960 this cliff edge has sometimes been visible and sometimes not -- depending on the cycle of surges and ice wastage episodes.

The pattern of surges and retreats on Kaldalonsjökull from 1740 to the present day.  After Brynjolfsson et al, 2015.  Note the most recent surge of 1 km betwewen 1995 and 1999, which has been followed by a very rapid ice edge retreat.

Between 1940 and 1994 there was a continuous retreat of the ice edge of 1.5 km;  when we first visited in 1960 the effects of this ongoing retreat were clearly displayed.  The surge of 1994-99 pushed the ice edge forward by 1015m, and the rapid retreat that followed has seen the ice edge retreat further into the trough head than the 1994 position.

Brynjólfsson, S., A. Schomacker, E. R. Guðmundsdóttir and Ó. Ingólfsson. 2015. A 300-year surge his- tory of the Drangajökull ice cap, northwest Ice- land, and its maximum during the ”Little Ice Age”. Holocene 25(7), 1076–1092. http://doi.org/10.1177/- 0959683615576232

Abstract

Over the last 300 years, each of the three surge-type outlet glaciers of the Drangaj.kull ice cap in northwest Iceland has surged 2–4 times. There is valuable historical information available on the surge frequencies since the ‘Little Ice Age’ (LIA) maximum because of the proximity of the surging outlets,
Reykjarfjar.arj.kull, Leirufjar.arj.kull and Kaldal.nsj.kull, to farms and pastures and monitoring of these glaciers since 1931. We have reconstructed the surge history of the Drangaj.kull ice cap, based on geomorphological mapping, sedimentological studies and review of historical records. Geomorphological mapping of the glacier forefields reveals twice as many end moraines as previously recognized. This indicates a higher surge interval than earlier perceived. A clear relationship between the surge interval and climate cannot be established. Surges were observed more frequently during the 19th century and the earliest 20th century compared with the relatively cool 18th century and the late 20th century, possibly reflecting a lack of information rather than a long quiescent phase of the glaciers. We have estimated the magnitude of the maximum surge events during the LIA by reconstruction of Digital Elevation Models (DEMs) that can be compared with modern DEMs. As reference points for the digital elevation modelling, we used the recently mapped lateral moraines and historical information on the exposure timing of nunataks. During the LIA maximum surge events, the outlet glaciers extended 3–4 km further down-valley than at present. Their ice volumes were at least 2–2.5 km3 greater than in the beginning of the 21st century.