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Harriman Expedition Retraced

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Kristine J. Crossen

Alaska's Glaciers

The most extensive glaciated terrain in Alaska surrounds the Gulf of Alaska and Prince William Sound. High precipitation rates coupled with high mountainous areas produce the optimal situation for ice masses to form and flourish. The Harriman Expedition Retraced viewed hundreds of glaciers, many of them unnamed, in Glacier Bay, Prince William Sound, the Kenai Mountains and the Aleutian Range. One of the most significant scientific feats of the 1899 Harriman Expedition was the discovery and naming of Harriman Fiord, as well as the naming of the numerous glaciers in College and Harriman Fiords. Well-known glaciers seen on this trip included Grand Pacific, Margerie and Lamplugh Glaciers in Glacier Bay, Hubbard Glacier near Yakutat, Columbia Glacier in Prince William Sound, Harriman and Barry Glaciers in Harriman Fiord, and Smith Glacier in College Fiord.

 

harriman glacier

Left side of Harriman Glacier in 1994. This is one of the few tidewater glaciers currently advancing. This view of the extreme right side at low tide, shows the shoal that provides the footing for the glacier to advance (Photo by Kristine Crossen).
Click image for a larger view.

Glaciers form when snow compresses and recrystallizes into ice, and then flows down slope picking up debris and eroding the underlying bedrock. Climate change affects glaciers when additional precipitation or cooling temperatures add mass to the glacier, allowing it to advance down valley. Climate strongly controls the dynamics of glaciers that terminate on land and lose ice (ablate) by melting mechanisms.

serpentine glacier 1899

In 1899, Serpentine Glacier flows in a sinuous pattern down the valley, exhibiting white ice all the way to the terminus at the shoreline (Photo by Edward S. Curtis).
Click image for a larger view.

Principles of glacier formation, ice flow, and glacial landforms were well understood at the time of the original Harriman Expedition, and Alaskan examples were well documented by G.K. Gilbert and John Muir. Sharp-peaked horns and arêtes, high cirque basins, and steep-sided U-shaped valleys sculpted by glacial ice were documented in southern coastal Alaska. Many examples of morainal ridges and large outwash streams pouring from the glaciers were also seen.


serpentine glacier 1998

Serpentine Glacier in 1998, showing a black surface covered with debris, indicating a stagnant glacier front (Photo by Kristine Crossen).
Click image for a larger view.



In comparison, recent studies of glaciers have lead to a better understanding of both climate change during the Little Ice Age and the dynamics of tidewater glaciers.

The Little Ice Age is a period of cold climate from approximately 1350 to 1850 AD. Glacial activity, historic records, tree rings, and Native oral history all give evidence of ice advance that overran forests. During the 1800's many glaciers began spectacular retreats in response to climatic warming at the end of the Little Ice Age. This continues today with most Alaskan glaciers in retreat. This results in stranded moraines, abrupt trimlines, reduced ice volumes, stagnant ice masses, and vegetation recolonizing deglaciated areas. In addition, ice retreat has also uncovered forests around the Gulf of Alaska previously overrun by the ice.

 

Barry Glacier 1899

Terminus of Barry Glacier in 1899 near Point Doran, showing the ice caves where englacial streams exited the ice (Photo by C. Hart Merriam).
Click image for a larger view.



Barry Glacier 1998

Terminus of Barry Glacier, 1998. Note the three individual glaciers separated by bedrock walls. From the left are Cascade, Barry, and Coxe Glaciers respectively. These glaciers retreated over 3 miles in 15 years, and have occupied their current positions since 1914 (Lethcoe, 1987). (Photo by Kristine Crossen).
Click image for a larger view.

 

Recent research into tidewater glacier dynamics was lead by studies at Columbia Glacier; important because of the icebergs it calves into the shipping lanes in Valdez Arm. This glacier acted as a natural laboratory when it began its catastrophic retreat in the 1970's, and taught glaciologists that the depth of water at the ice terminus was the strongest forcing factor affecting the dynamics of tidewater glaciers. Iceberg calving rate and thus retreat rate were directly tied to the water depth, as deep water caused more ice to come afloat and calve away., thus causing increased retreat . Tidewater glaciers commonly terminate in a vertical face with ice that extends 200-300 feet above the water line and as much as 1000 feet below water to the fiord floor. Within the last 200 years, catastrophic retreat has occurred in many fiords including Glacier Bay, Disenchantment Bay, Columbia Bay, College Fiord and Harriman Arm. Catastrophic retreat of the glacier continues until the glacier leaves deep water, commonly at the head of the fiord. Most recently, Columbia Glacier has retreated nearly 10 miles in the past 25 years.

Barry Arm

Aerial view of Barry Arm showing Cascade Glacier on the left and Barry Glacier on the right (Photo by Kristine Crossen).
Click image for a larger view.

The Harriman Expedition of 1899, at the end of the Little Ice Age, saw a mixture of tidewater glaciers, some having undergone prior retreat (in Glacier Bay) and others still filling their respective fiords (like Columbia Glacier). In Prince William Sound, they were able to "sneak" the G.W. Elder past the extended terminus of Barry Glacier to discover Harriman Fiord.

During the Harriman Expedition Retraced 2001, most of the glaciers terminating on land and many of the tidewater glaciers have been in retreat for at least 100 years. Barren trimlines, debris covered stagnant ice, and decreased ice masses show the glacier's response to 100 years of warming. However, a few tidewater glaciers are advancing, in response to forcing factors related to water depth and fiord sedimentation. Harriman, Hubbard, and Yale Glaciers are all advancing by building morainal shoals that they are then able to advance onto and bulldoze or redeposit ahead of them as they move down the fiord.

map of Barry Glacier 1899

1899 map of Barry Arm showing Barry Glacier extending to within 1000 feet of Point Doran, where the G. W. Elder squeezed along the ice margin into Harriman Fiord. Note the 3 major tributaries to this glacier.
Click image for a larger view.



References:

Lethcoe, N.R., 1987, Glaciers of Prince William Sound, Prince William Sound Books, Valdez, 151 p.


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For information on the Harriman Retraced Expedition e-mail: harriman2001@science.smith.edu

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