Browse: Alaska Glaciers Case Study

Anchorage, Alaska and Region 
Satellite image of Anchorage, AK region. Note Cook Inlet (SW, lighter blue tone), and Prince William Sound (SE, darker blue tone). Matanuska Glacier is in the NE portion of the image.

The Portage Glacier:
Portage Creek, Alaska
Portage Creek below Portage Lake. Note the water color that results from the sediment load of glacial rock flour.
Portage Lake, Alaska
Map of Portage Lake and tributary glaciers.
Portage Lake, Alaska
View of Portage Lake from the terminal moraine (that dams the valley and creates the lake) near the visitors center.

Portage Lake, Alaska
View of the terminal moraine from Portage Lake.

Portage Lake, Alaska
Portage Lake, Burns Glacier (L) and Portage Glacer (R) in June 2007.
Portage Glacier, Alaska
Portage Glacier. Note the medial moraine.
Portage Glacier, Alaska
Portage Glacier calving into the lake.
Portage Glacier, Alaska
Portage Glacier. Note the discharge of sub-glacial water and sediment along the valley wall.
Portage Lake, Alaska
Dr. Kristine Crossen (Univ. of Alaska Anchorage) discussing a photo from 1910-1915 showing the same landscape behind her in the modern photo. Note that in the historic photo (reproduced below) Portage Glacier extended nearly to the terminal moraine, seen at the end of the lake today.

Portage Lake, Alaska
"The Canyon", 1910-1915 photograph by P.S. Hunt, showing the west end of Portage Glacier. Compare this view with the 2007 photo above.

Source: Anchorage Museum of History and Art.

Portage Lake, Alaska
Dr. Kristine Crossen (Univ. of Alaska Anchorage) on the terminal moraine at end of Portage Lake. Dr. Crossen used lichenometry and tree ring analysis to date the moraine to 1852.

Portage Glacier, Alaska
Portage and Burns Glaciers chronology. Note that Portage Pass was used as a key transportation route to get from Prince William Sound to Turnagain Arm (Cook Inlet) and on to Anchorage prior to the WWII railroad tunnel through the mountain.

Portage Glacier, Alaska
1951 aerial photograph of Portage Glacier and Portage Lake. Notice the large number of icebergs in the NE end of the lake.

Portage Glacier, Alaska
1983 aerial photograph of Portage Glacier and Portage Lake. Notice the substantial glacial retreat since the 1951 image.

The Matanuska Glacier:
Matanuska Glacier, Alaska
Matanuska Glacier terminus. Note the terminal moraine just beyond the modern glacier.
Matanuska Glacier, Alaska
Terminal moraine of the Matanuska Glacier. The relatively clean ice in the background is moving much more quickly than the sediment-rich ice in the foreground. Maximum velocity at the terminus is approximately 1 foot/day.
Matanuska Glacier, Alaska
Dr. Kristine Crossen (Univ. of Alaska Anchorage) showing a shear plane on the Matanuska Glacier. Note the ice axe indicates the dip. Cleaner ice (left) is flowing at a faster rate than dirtier ice (right) and overriding it, much like a reverse fault.
Matanuska Glacier, Alaska
Matanuska Glacier terminus. Note that much of the rocky sediment in the foreground is underlain by glacial ice. The position of the terminus has changed relatively little in the past 30 years.

Matanuska Glacier, Alaska
Dr. Kristine Crossen (Univ. of Alaska Anchorage) clearing a 5-10cm cover of sediment off the surface of the Matanuska Glacier, exposing the cleaner ice below.

Matanuska Glacier, Alaska
View into the ice of the Matanuska Glacier. Note the entrapped bubbles and sediment.
Matanuska Glacier, Alaska
Abundant meltwater and sediment at the terminal moraine of the Matanuska Glacier.
Matanuska River, Alaska
The Matanuska River several miles below the Matanuska Glacier. Note the Holocene terrace just beyond the river and the loess and dune deposits in the bluff (foreground).
Prince William Sound Tidewater Glaciers:
Dutch Harbor, Alaska
Original members of the Harriman Expedition on the wharf at Dutch Harbor, 1899. Source: PBS.
Prince William Sound, Alaska (College Fiord)
The Elder steams past Wellesley Glacier, photographed by C. Hart Merriam, 1899. Source: PBS.
Prince William Sound, Alaska (College Fiord)
Barnard, Wellesley, and Vassar Glaciers in 2007.
Prince William Sound, Alaska (College Fiord)
Harvard glacier (background) with medial moraines. Note the substantial till entrapped in the iceberg (foreground).
Prince William Sound, Alaska
Marine chart for portions of College Fiord and Harriman Fiord within Prince William Sound, AK. During the 1899 Harriman expedition, three glaciers (Barry, Coxe, and Cascade) had coalesced and extended almost to the junction of Barry Arm and Harriman Fiord (note moraines on chart - shown in light blue tone). The captain of the Elder navigated through a small channel between the glacial terminus and the valley wall, discovering Harriman Fiord. The glaciers subsequently retreated to their present position by the 1930s and have changed relatively little since.
Prince William Sound, Alaska (Barry Arm) 
Barry Glacier and Doran Strait at the mouth of Harriman Fiord, Alaska, June 1899. Photographed by C. Hart Merriam. Source: University of Washington.
Prince William Sound, Alaska (Barry Arm) 
Cascade (left) and Barry (right) Glaciers, at the head of Barry Arm, Prince William Sound, AK, June 2007. Note the extent of open water that was filled with glacier ice in the 1899 photo.
Prince William Sound, Alaska (Barry Arm) 
Coxe Glacier. Note the lateral moraine and subglacial meltwater flow on the right.

Prince William Sound, Alaska 
Coxe Glacier. Note the lateral moraine and subglacial meltwater flow on the right.

Prince William Sound, Alaska (Barry Arm) 
The front of Barry Glacier, photographed by C. Hart Merriam, 1899. Source: PBS.

Prince William Sound, Alaska (Barry Arm) 
The Barry Glacier in 2007. Note the layer of brittle ice with crevasses on top (to approximately 100’ depth) and the more solid plastic ice below.

Prince William Sound, Alaska (Barry Arm) 
Ice calving from the terminus of Barry Glacier.

Prince William Sound, Alaska (Harriman Fiord) 
The Harriman Fiord and Surprise Glacier, named after the Harriman expedition discovered this fiord by navigating the narrow channel between the Barry Glacier and the valley wall.