Landsat satellite data, collected and processed by the U.S. Geological Survey, illustrate the retreat of the terminus of Bear Glacier in southern Alaska.
Bear Glacier is one of the larger outlet glaciers flowing from the northeastern part of Harding Icefield toward Resurrection Bay in the Kenai Fjords National Park in the Kenai Mountains. The park is a popular area for camping, hiking, exploring, and photography.
In 1809, Bear Glacier was 26 km long and ended about 300 m from the shore of Resurrection Bay. Since that time, the terminus has gradually melted and calved icebergs, retreating 400 m before 1950 and another 1,500 m between 1950 and the mid-1990s. Substantial retreat has occurred in the last 15 years. By 2000, the terminus of Bear Glacier was actively calving large numbers of icebergs, and the small marginal lake that had developed by 1950 was quite large. By 2004, the glacier had retreated more than 2 km farther, and by 2010, about another kilometer.
Scientists are using the Landsat data, along with other data and field monitoring, to examine conditions in the region as possible indicators of long term regional warming. For more information about the glaciers of Alaska, see U.S. Geological Survey Professional Paper 1386-K, Glaciers of Alaska.