October 11, 2017
Steenstrup Glacier, NW Greenland Releases New Island in 2017
Posted by Mauri Pelto
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.