March 22, 2017
Landsat images of Hallo Glacier in 1985 and 2015 indicating the 1985 terminus position red arrows and yellow dots indicate 2015/2016 terminus location. Purple dots show the snowline
Hallo Glacier is one of the larger glaciers in Katmai National Park draining east from Mount Steller and ending in an expanding proglacial lake east of Hallo Bay. Hallo Bay is well known as a good location for brown bear watching (NPS). Arendt and Larsen (2012) assess the glacier changes in Alaska National Parks they provide a map of the change in glacier extent from 1956-2009, Figure 7. This indicates a significant retreat but it is not quantified. They further note a 15% decrease in areal extent of Katmai Region glaciers from 1956-2009. Giffen et al (2015) indicate the glacier retreated 900 m from 1951-1987 and then advanced 150 by 2000. Here we utilize Landsat imagery to examine retreat from 1985 to July 2016 to examine the glaciers response.
In 1985 the glacier terminated just off the western shore of a small island in the lake. The terminus front in the lake measured 3000 m in length. The snowline averaged 1050 m across the glacier. By 1995 little retreat had occurred, the snowline was averaged 1050 m. In 2000 the glacier terminus had changed little from 1985. The average snowline was at 1100 m. In 2015 the terminus had retreated 600 m from the island and 800 m along the northern shore of the lake. The snowline is at 2000 m. In 2016 the snowline is averages 1150 m , the highest observed. The terminus front in the lake remains 3000 m long. The rate of retreat increased after 2000, and the glacier is poised for additional retreat. A 2013 Google Earth image illustrates that the lower 3.5 km of the glacier has a low slope and limited crevassing, except for minor crevassing along southern calving front. This indicates the lake is likely to expand at least to this point. Further that the glacier is poised for continued significant retreat and lake expansion. The retreat is less than, but similar to that of nearby FourPeaked and Spotted Glacier.
1995 Landsat image of Hallo Glacier indicating the 1985 terminus position red arrows. Purple dots show the snowline
2000 Landsat image of Hallo Glacier indicating the 1985 terminus position red arrows and yellow dots indicate 2015/2016 terminus location. Purple dots show the snowline
2016 Landsat image of Hallo Glacier indicating the 1985 terminus position red arrows. Purple dots show the snowline.
2013 Google Earth image of Hallo Glacier, note low uncrevassed terminus tongue in lower 3.5 km.