Conrad Icefield Retreat, Selkirk Mountains, British Columbia

Conrad Icefield is at the northern edge of the Bugaboos in the Purcell Range of the Selkirk Mountains in southwest British Columbia. The icefield feeds several terminus tongues primarily the Conrad Glacier and Malloy Glacier, both of these have two arms. In the case of Conrad Glacier the two arms still join above the terminus, while for Malloy Glacier there are now separate termini. conrad icefield map
British Columbia Topographic Map of the Conrad Icefield area

Here we examine the terminus changes of these from 1998 to 2013 using Landsat images from 1998 and 2013 and Google Earth images from 2005. The pink arrow for Malloy Glacier and yellow arrow for Conrad Glacier are in fixed locations on each image. In the 1998 image and map above the west terminus of the Malloy Glacier, pink arrow, reaches to the shores of an unnamed lake at the head of Malloy Creek, the south terminus ends just short of the lake. Conrad Glacier extends past the yellow arrow to end at what is the beginning of a proglacial lake in 1998 that is not in evidence on the map. By 2005 in the Google Earth image the west terminus of Malloy Glacier has retreated a short distance from the lake shore and the southern terminus has retreated 150 m from the lake. Conrad Glacier has retreated upvalley of the yellow arrow. A closeup view of the Malloy Glacier terminus, red arrows, from 2005 indicates that the southern terminus is quite stagnant below the icefall and retreat is continuing. The west terminus is quite narrow and ending on a steep slope, with a buttress paralleling the north side of the terminus ending at the orange arrow. The Conrad Glacier terminus is stagnant beyond the knob at Point A, and is only 200 meters wide from Point A to Point B. The proglacial lake beyond the Conrad Glacier terminus is now 400 m long and the terminus has just retreated upvalley of the lake. In 2013 Malloy Glacier western terminus is at the top of the buttress, orange arrow ending 250 m from the lake, pink arrow. The southern terminus has pulled back 250-300 m from the lake. Malloy Glacier has undergone a 250 m retreat from 1998-2013. Conrad Glacier has retreated a significant distance from the proglacial lake, and now ends on a line between the knob at Point A and B. The proglacial lake has filled in at its upstream end a small amount, hence the distance from the downstream end of the proglacial lake to Point A is a better measure of the retreat from 1998 to 2013. This distance is 700 m, however the retreat is between 600 and 700 m as the lake had begun to form in 1998. Another measure is the distance from where the two arms of Conrad Glacier join to the terminus. The upglacier joining has experienced little change. This distance is in 1.7 km 1998 and just under 1 km in 2013, also indicative of close to 700 m of retreat in 15 years.conrad icefield 1998
1998 Landsat image of Conrad Icefield
conrad icefield ge
2005 Google Earth image of Conrad Icefield
conrad icefield east terminus 2005
2005 Google Earth image of Malloy Glacier terminus
conrad icefield main terminus 2005
2005 Google Earth image of Conrad Glacier terminus
conrad icefield 2013
2013 Landsat image of the Conrad Icefield

Examination of the margins of both glaciers above the icefalls 1 km above the terminus in 2005 indicates thinning and downwasting, red arrows, suggesting reduced flow that will drive continued retreat. The distance to the lake of the Malloy Glacier west terminus is seen in an image from Gery Unterasinger, Vertical Unlimited mountain guide. He also has a nice image showing the stagnant nature of the southern terminus below the icefall, both images are from 2010. These glaciers are retreating faster than Bugaboo Glacier, but not as fast as Vowell Glacier also in the Bugaboos. The retreat observed in the southern interior ranges of British Columbia, has been 15% from 1985 to 2005 (Bolch, 2010). malloy glacier margin

conrad glacier marginmalloy terminus

malloy west


2 thoughts on “Conrad Icefield Retreat, Selkirk Mountains, British Columbia

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