May 14, 2012
The Eel Glacier flows north from the Mount Anderson massif in Olympic National Park. This post examines imagery of the glacier from 1961, 1990 and 2009. The glacier has retreated 180 meters from 1990 and 2009, approximately 10 meters/year. The retreat rate has accelerated from the 5 meters/year from 1960-1990. The glacier has lost half of its area since first photographed in 1927 (NPS). What is of greater concern than the terminal retreat is the upglacier thinning during this period. In 1990 the glacier was receiving considerable contributions from the east and west slope of the mountain, near blue arrows. By 2009 the main glacier is nearly separated from the flow from the east and west valley sides. There has been considerable expansion of the blue arrows of bare rock areas that had been underneath glacier ice in 1990. The orange line is 1990 terminus, green line 2009. The loss of connection indicates thinning high up on glacier, that changes the very nature of the glacier from 1960 (top image) to 2009 (bottom image), the blue line is the 1960 terminus. . The retreat of this glacier is less severe than Anderson Glacier just over the pass, and is more like that of White Glacier. The mass loss follows that of North Cascade glaciers where thinning on most glacier has occurred from the terminus to the top of the glacier.