Steenstrup Glacier, NW Greenland Releases New Island in 2017

Steenstrup Glacier front in 2015 and 2017 illustrating location with respect to the new islands at: Red Head-red arrow, Tugtuligssup Sarqardlerssuua at yellow arrow , and the 2017 new island at orange arrow.  Yellow dots indicate icefront and purple arrow another future island to be released from the glacier.  

Steenstrup Glacier is located at 75.2 N in Northwest Greeland terminating in Melville Bay. The glacier terminates on a series of headlands and islands, the glacier immediately to the south is Kjer Glacier. The boundary between Steenstrup Gletscher and Kjer Glacier is Red Head and Steenstrup Glacier’s northern margin is at Cape Seddon. A previous post examined changes in the terminus position of Steenstrup and Kjer Glacier from 1999 to 2013 including formation of a new island at Red Head.  Another post in 2014 examined the formation of an additional island at Tugtuligssup Sarqardlerssuua.  Here we report formation of another new island at the glacier front in 2017 that is southwest of the Kloftet Nunatak.  The islands act as pinning points stabilizing the front, when a connection is lost there is typically a significant retreat of the glacier in the vicinity of the new island. 

In 1999 the Front of Steenstrup was pinned on three headlands at the yellow, orange and red arrows.  By 2005 the glacier had retreated from Red Head (Van As, 2010).  By 2013 the connection of ice at the yellow arrow at Tugtuligssup Sarqardlerssuua was thin and on the verge of failure which did occur in 2014.  In 2015 the connection to the pinning point at the orange arrow was thinning, this continued in 2016 and failed in 2017 creating a new island.  Retreat from Red Head 2005 to 2017 is 6 km, retreat from the orange arrow pinning point from 2016 to 2017 is 4 km and retreat at Tugtuligssup Sarqardlerssuua from 1999-2017 is 3 km.  The ice front is approaching Kloftet Nuntak just south of the purple arrow. McFadden et al (2011) noted several glaciers in Northwest Greenland Sverdrups, Steenstrup, Upernavik, and Umiamako that had similar thinning patterns. Each glacier also had a coincident speed-up with a 20% acceleration for Steenstrup Glacier (McFadden et al, 2011). This is a familiar pattern with thinning there is less friction at the calving front from the fjord walls, pinning points and the fjord base, leading to greater flow. The enhanced flow leads to retreat and further thinning, resulting in the thinning and the acceleration spreading inland.  Changes in the position of the ice front can also be viewed at  the Polar Portal.

Steenstrup Glacier front in 1999 and 2017 illustrating location with respect to the new islands at: Red Head-red arrow, Tugtuligssup Sarqardlerssuua at yellow arrow , and the 2017 new island at orange arrow.  Yellow dots indicate icefront and purple arrow another future island to be released from the glacier.  

Steenstrup Glacier front in 2016 indicating connection still to the pinning point that becomes an island in 2017, orange arrow.

Upernavik Glacier Retreat, NW Greenland

Box and Decker (2011) focused on the changes in the terminus of 39 Greenland Outlet glaciers from 2000-2010. Of these 35 had experienced net loss with the collective loss of 1593 km2 over the last decade. (Box and Decker, 2011). The retreat has occurred irrespective of the different characteristics of various glaciers (Bailey and Pelto, SkS) One of the glaciers in this group is Upernavik Glacier on the NW Greenland Coast. The Upernavik Glacier refers today refers to an increasing number of separate termini that were one termini up through 1950. Jason Box of Ohio State focused on the different termini in a 2008 post, commenting on the separation of termini A and B. Here we will focus on the development of two new islands between 2002 and 2010 due to the retreat of termini C as identified by Box and Benson in the image below. There are three marginal rock islands at the icecap periphery that are consistently labeled in the images below A, B and C. In addition the two arrows indicate two former nunataks, surrounded by ice in the 2002 Landsat image (top image below), and are now becoming rock islands at the glacier front in both Landsat 2010 (middle two images) and MODIS 2011 image (bottom). In the closeup Landsat image the glacier front is indicated in orange, beyond the terminus the fjord is still filled with considerable glacier debris that has calved. The black lines in the image are the uncorrected scan lines. A 2013 Landsat image indicates changes along outlet A as island at Point X, Y and Z emerge from the ice compared to 2002. upernavik2002 upernavik 2013
2013 Landsat image
Google Earth currently has an image that predates the development of the new island as well. This is not the only new island in Greenland by any means. Warming Island on the east coast has gained notoriety. It is seen below in a nice August 2010 Landsat image. Box and Decker (2011) note that ice loss for Upernavik Glacier’s combined termini was 7.9 square kilometers per year from 2000-2010, in Table 2. For the 2002 to 2010 period it is evident the Upernvavik terminus C lost at least 35 square kilometers as the two new islands begin to develop, mostly between 2002 and 2008. This glacier follows the pattern of Umiamako Glacier and Jakobshavn Glacier. It also is worth noting it has a deep bed that extends well under the ice sheet as observed by Morligheim et al (2014). upernavik base