Bainbridge Glacier, Port Bainbridge

Bainbridge Glacier, Port Bainbridge

by | Jan 22, 2022

Bainbridge Glacier starts on Pinnacle Mountain at the edge of the Sargent Icefield on the Kenai Peninsula, and flows generally east for 10 miles (16 km) to Port Bainbridge, about 47 miles (76 km) south-southeast of Whittier and 36 miles (58 km) east of Seward, Alaska. The glacier name was first reported in 1905 by Ulysses S. Grant of the U.S. Geological Survey and was widely known and used locally. Port Bainbridge is a fjord off the east coast of the Kenai Peninsula named in 1794 by Captain George Vancouver in honor of John Bainbridge who was an astronomer of the 17th century. Port Bainbridge is about 3 miles (4.8 km) wide and 12 miles (19 km) long with depths reaching 870 feet (265 m). The head of the fjord is a low saddle with an elevation of about 200 feet (61 m) and about 1 mile (1.6 km) wide leading to Icy Bay. Bainbridge Glacier and three smaller glaciers to the north are on the western shore of Port Bainbridge. The eastern shore is mostly formed by Bainbridge Island and is broken by Bainbridge Passage, Prince of Wales Passage, and Elrington Passage that connect with Prince William Sound. The Sargent Icefield was named in 1952 by U.S. Geological Survey for Rufus H. Sargent, a topographer who did extensive exploration and mapping on the Kenai Peninsula. The icefield has many outlet glaciers that descend the eastern slope toward or into Prince William Sound at Kings Bay, Port Nellie Juan, Nassau Fjord, Icy Bay, and Port Bainbridge. Glaciers also cascade from the southern slope toward the Gulf of Alaska at Puget Bay, Johnstone Bay, and Whidbey Bay. Prince William Sound and the Kenai Peninsula region consist of one of the world’s largest geological accretionary complexes. Paleozoic through Cenozoic age rocks underlie the southern coast of Alaska and form tectonically stratified terranes that assembled into their present positions in the Cretaceous and Cenozoic. The Chugach and Prince William terranes are a MesozoicQuaternary accretionary complex that consists of turbidites that are exposed for about 1,367 miles (2200 km) along the southern Alaska coast. In Prince William Sound, the turbidites of the Chugach and Prince William terranes are known as the Valdez and Orca Groups. The Sargent Icefield caps a portion of the Orca Group which consists of thick layers of turbidite sedimentary rocks including sandstone, siltstone, mudstone, and conglomerate that represent ancient submarine fan deposits. The sedimentary layers were intruded by plutons about 50 million years ago indicating accretion by the middle Eocene. Prince William Sound was extensively glaciated during the Pleistocene and glacial deposits record Late Wisconsin glaciation and earlier ice advances. The earliest human migrants into the region probably found an inhospitable landscape dominated by embayments filled with glacier ice and limited vegetated flats.

The Chugach people of Prince William Sound have historically identified themselves as Alutiiq, the Sugpiat word for ‘Aleut‘ since at least 1851. The Russians referred to all coastal Alaska Natives as Aleuts. Alaska Natives of the region today live mostly at Chenega, about 13 miles (21 km) east-southeast of Bainbridge Glacier, and refer to themselves as Aleut, Alutiiq, and Sugpiat, but Sugpiat is becoming the accepted term. The Sugpiat traditionally inhabited the coast from the Kodiak Archipelago north to the Kenai Peninsula, and east into Prince William Sound as far as Kayak Island. Traditional winter homes were semi-subterranean structures called barabaras, and summers found were spent at seasonal fish camps. Prince William Sound was first partially explored by Captain James Cook on his third voyage to the Pacific in May 1778. Subsequently, Russians carried on explorations in 1781, 1788, and 1793. By 1790, the Russians had established sea otter hunting stations in the sound and were rapidly depleting the population. In 1794, Vancouver arrived to explore the sound for a possible northwest passage and Lieutenant Joseph Whidbey traveled in a small boat south along the coast of western Prince William Sound. In 1887, a thorough exploration of western Prince William Sound was made by Samuel Applegate in the schooner Nellie Juan. Although Applegate never published his account, the voyage was carefully studied and summarized by George Davidson. After interviewing Applegate, Davidson wrote a description of the features seen by Applegate in the western part of the sound and published this along with Applegate’s map. This map is the earliest reference for many Prince William Sound glaciers. In 1905, 1908, and 1909, Grant and Daniel F. Higgins studied the geology of Prince William Sound for the U.S. Geological Survey and were the first to discover many of the glaciers and to make photographs that have since been invaluable as a reference point for present-day glaciologists.

In 1905, Grant and Higgins explored Port Bainbridge and documented the tidewater Bainbridge Glacier and three smaller glaciers that were no longer tidewater on the western side of Port Bainbridge. They did not approach the terminus of Bainbridge Glacier until 1908 when they made detailed observations. They observed fresh push moraines along the glacier’s margin, some with freshly embedded trees and debris indicating a recent advance. No further recorded visits to Bainbridge Glacier were made until 1957 when photographs were taken from the same stations used by Grant and Higgins. A baseline was measured and four photo stations were re-occupied. A botanist also dated the vegetation on the moraines and at the glacier trim line. The expedition found that the ice position had changed very little since 1908. However, a study in 1967 determined that the glacier experienced another advance around 1934 and overrode its 1908 moraine. By 2000, the terminus of the Bainbridge Glacier had retreated about 1,000 feet (300 m) from the moraine that now forms the head of a small embayment on the western shore of Port Bainbridge and most of the glacier terminus was fronted by an arcuate ice-marginal lake. A well-vegetated braided outwash plain is located on the southern side of the glacier’s terminus. This remarkable stability indicates near-equilibrium conditions for this glacier where the firn line, and consequently the accumulation area, are still well above the critical elevation that would increase the ablation area. However, any further upward movement of the firn line will affect the accumulation area quite seriously. Thus if the slow upward movement of the firn line continues, as suggested by the retreating terminus, it will affect frontal behavior considerably. Read more here and here. Explore more of Bainbridge Glacier and Port Bainbridge here:

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This ‘warming stripe’ graphic is a visual representation of the change in global temperature from 1850 (top) to 2021 (bottom). Each stripe represents the average global temperature for one year. The average temperature from 1971-2000 is set as the boundary between blue and red. The color scale goes from -0.7°C to +0.7°C. The data are from the UK Met Office HadCRUT4.6 dataset. 

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