September 11, 2015

Hess Mountain Glacier Retreat, Yukon

Posted by Mauri Pelto

In the Selwyn Mountain Range, Yukon at the headwaters of the Hess River is the Hess Mountains and Keele Peake the highest peak in the region. A series of glacier radiate from this region. The Yukon Territory is host to numerous small alpine glaciers that have been rapidly losing area and volume.  From 1958-2007 glaciers lost 22% of their volume in the Yukon (Barrand and Sharp, 2010).  Due to the high snowlines David Atkinson, at University of Victoria notes the rate of retreat has increased since then, and is using weather stations to identify the specific conditions driving the ice loss. Semmes and Ramage (2013 ) observed in the Yukon River Basin from 1988 to 2010 a significant lengthening of melt duration t with earlier melt onset in high elevations  and significant later end of melt refreeze in theintermediate elevations (600 to 1600 m). Here we examine in particular a glacier draining southeast from the Hess Mountains that feeds the Hess River using Landsat imagery from 1986 to 2015.
hess map

In this Canadian Toporama image the glacier of primary interest has flow indicated by the blue arrows.

In 1986 the glacier extended to within a 100 meters of an alpine lake, with the terminus indicated by the red arrow.  The glacier was joined near the terminus by a tributary at the yellow arrow.  At the pink arrow a separate glacier terminus is formed by the merging of two glaciers.  In 1992 the main glacier tongue has retreated further from the lake.  By 2015 the tributary no longer is connected to the main glacier and terminates 600 meters above the valley.  The main glacier terminus has retreated 800 meters since 1986, and is now just over 3 km long. The terminus area at the glacier flowing north at the pink arrow, is no longer formed by the merging of two glacier termini, as two distinct termini exist.hess 1986

1986 Landsat Image

hess 1992

1992 Landsat Image

hess 2015

2015 Landsat Image