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A Century of Retreat at Portage Glacier, South-Central Alaska

December 13, 2006

Introduction: The Portage Glacier, in south-central Alaska, is viewed by thousands of visitors annually who come to the U.S. Forest Service Begich, Boggs Visitor Center located on the road system between Anchorage and Whittier, Alaska. During the past century, the terminus of the glacier has retreated nearly 5 kilometers to its present location (fig. 1). Like other glaciers that terminate in water, such as Columbia Glacier near Valdez or Mendenhall Glacier near Juneau, Portage Glacier has experienced accelerated retreats in recent decades that likely were initially triggered by climate change begun at the end of the Little Ice Age in the mid-1800s and subsequently controlled in recent history primarily by calving of the glacier terminus. Photographic records of the terminus covering 1914 until present day track the patterns of retreat. These data, coupled with USGS climate information collected from the southern end of the ice field, provide insight to the patterns of retreat that might be observed in the future.

Publication Year 2006
Title A Century of Retreat at Portage Glacier, South-Central Alaska
DOI 10.3133/fs20063141
Authors Ben W. Kennedy, Dennis C. Trabant, Lawrence R. Mayo
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Fact Sheet
Series Number 2006-3141
Index ID fs20063141
Record Source USGS Publications Warehouse
USGS Organization Alaska Science Center