October 6, 2013
Inter Glacier Retreat-Demise, Mount Rainier Washington
Posted by Mauri Pelto
Inter Glacier is one of the smaller glaciers on Mount Rainier, Washington, lying between the larger Emmons and Winthrop Glacier. The glacier now extends from 2800 to 2200 m, with recent retreat shortening the glacier to 1 km in length. This post examines the retreat from 1992 to 2013 using Landsat imagery, Google Earth imagery and pictures from 2013 from Tyler Christensen.
In 1992-1994 the glacier extends below a prominent knob on the east side of the glacier, red arrow. There are also only two bedrock knobs protruding through the glacier surface. The 1994 margin in the Google Earth image is a red line.
Landsat Image 1992
By 2009 the glacier has thinned considerably and retreated 200 m, terminus indicated by green line. There are five outcrops of rock that now protrude through the thinning glacier, see dark green arrows. The thin stagnant nature of the lower glacier indicates the retreat will continue. The 2013 Landsat image indicates the glacier has retreated beyond the bedrock knob east of the glacier, red arrow and to the bedrock knobs that had been amidst the glacier on its east side. The glacier 2013 terminus is indicated with pink dots on the 2012 and 2013 image below. The last two images are from Tyler Christensen who was climbing on Mount Rainier in August, 2013. The first picture is from below the terminus, indicating the stagnant nature of the lower glacier and emerging bedrock. The second image is a view east across the glacier at 2400 m, indicating the lack of crevassing, the number of emerging bedrock higher on the glacier, and the lack of snowcover with six weeks left in the melt season. All three of these observations indicate a glacier that cannot survive (Pelto, 2010).
This glacier is responding like all Mount Rainier glaciers, retreating. Inter Glacier is a smaller glacier like Paradise Glacier, and like Paradise Glacier it will not survive current climate. There is limited detailed study of Mount Rainier glaciers compared to Mount Baker (Pelto and Brown, 2012). With limited mass balance work on two glaciers Nisqually and Emmons. A detailed report on change in the termini is only up to 1994.