September 20, 2012

Mittie Glacier retreat, Ellesmere Island, Canada

Posted by Mauri Pelto

The Manson Icefield is in southeast Ellesmere Island, Canada. This icefield has the highest concentration of surging glaciers in the Canadian Arctic Islands (Copland et al, 2003). The Mittie Glacier is the largest such glacier and drains north from the icefield into Smith Bay. Mittie Glacier was noted to be advanacing and surging in 1999-2000 by Copland et al (2003). This surge led to an advance of about 4 km from the 1959 terminus position and peak velocities reached 1 km/year. During this surge extensive crevassing was noted from the terminus to 30 km inland. The surge was noted to continue up until 2008 (Sharp et al, 2011). mittie mapA surge is an episodic speed up of a glacier that also tends to lead to glacier advance, this post does not examined velocity data and can address if the surge has ended, here we examine a change in the terminus position of the primary Mittie Glacier and a secondary glacier just east of Mittie Glacier. Here we focus on 2002, 2010 and 2012 imagery to illustrate terminus change of Mitte Glacier. The terminus in each image is indicated by green dots. The 2002 terminus position of the Mittie Glacier is indicated by yellow arrows and the adjacent glacier that did not surge pink arrows in each image for comparison, the 2012 image at the point nearest Mittie Island in 2012 is indicated by a red arrow. In 2000 and 2002 Landsat imagery indicates the Mittie Glacier reaching to Mittie Island. By 2010 and 2012 the glacier has retreated from the island. The glacier has retreated on the northeast corner 4.5 km from Mittie Island. The smaller tributary to the east of the main Mittie Glacier has retreated approximately 1 km. The main change is that Mittie Island was a pinning point for the terminus of the glacier. Without this pinning point the glacier will experience enhanced terminus calving. The warm climate conditions of the last three summers and reduced sea ice duration in the area will increase the capacity for retreat of this glacier. The last images is a MODIS image from Aug. 30, 2012 indicating Mittie Island, yellow arrow, and the lack of sea ice in the vicinity of the glacier terminus. The retreat of the terminus from the pinning point is similar to that seen this summer on Thrym Glacier, Greenland.