January 31, 2012

Icemantle Glacier Retreat, British Columbia

Posted by Mauri Pelto

Icemantle Glacier is on the north side of Greenmantle Peak just north of Snowcap lake in southern British Columbia, viewed from the northeast in the Google Earth image below. It is not an often visited area and the glacier has not been previously assessed for its response to climate change. Other glaciers in the area have, the outlet glaciers of Snowcap Icefield lost 17% of there area in from 1987-2007. Stave Glacier has retreated 840 meters from 1977-2002 (Koch et al, 2009) . Just to the north Freshfield Glacier has retreated since. The glacier was mapped in 1987 and at that time no lake existed close to the terminus. The lake in 2006 is 500 meters across. The glacier is 160 meters from the lake, indicating a retreat of 660 meters from 1987, blue line. In a 2009 Ikonos image the glacier has retreated an additional 75 meters. The last image in the sequence indicates the 1987 terminus position blue and 2009 terminus red. The snowline on the glacier has been at least as high as 2000 meters in 2003-2006 and 2009. This leaves less than 35% of the glacier in the accumulation zone consistently. This is insufficient to maintain equilibrium and will drive continued retreat. The ongoing retreat is also evident from the thin nature of the current terminus, a small lake is also forming at the current terminus.