Amherst Glacier, College Fjord

Amherst Glacier, College Fjord

by | Sep 1, 2022

Amherst Glacier flows northwest for 4 miles (6.5 km) from the Chugach Mountains to a terminus lake, 5.5 miles (9 km) northeast of Point Pakenham in Prince William Sound, and 52 miles (83 km) southwest of Valdez, Alaska. The lake is drained by a river that flows about 2 miles (3.2 km) to a tidal flat 1 mile (1.6 km) south of Coghill Point on the eastern shore of College Fjord. The glacier was named in 1899 by members of the Harriman Alaska Expedition for Amherst College in Amherst, Massachusetts.

The Kenai, Chugach, and Saint Elias mountain ranges form an almost unbroken chain of peaks with elevations between 6,000 and 20,000 feet (2,000-6,000 m) around the northern Gulf of Alaska. This topographic barrier intercepts moist maritime air from the south resulting in heavy precipitation and the development of extensive icefields and valley glaciers. Recent reductions in glacier volume and variations in glacier length are among the strongest evidence of global warming. The response of glaciers to climate change during the Little Ice Age, from about 1300 to 1850, in northwestern North America has been well documented along the Alaskan Kenai, Chugach, Wrangell, and Saint Elias mountain ranges. Therefore, glacial observations from this maritime region provide an important paleoclimate record for understanding climate change over recent millennia and its linkages with the oceans.

During the Little Ice Age, the Amherst, Crescent, and Lafayette Glaciers were merged together. The maximum extent of the merged glacier terminus is preserved as forested moraines. Well-preserved logs have been found within these moraines and tree-ring dating of the logs indicate outer ring dates from 1633 and ages of trees growing on the outermost moraine indicate stabilization in about 1830. The glacier terminus has retreated about 1.6 miles (2.6 km) since the Little Ice Age maximum and currently terminates in a proglacial lake that formed sometime before 1935. Cross-dates of glacier killed trees on the forefield show that the margin was advancing in 1625. The outer moraine stabilized in about 1780 and two inner moraines, also dated with tree-rings, were ice-free in 1807 and 1935 respectively. Read more here and here. Explore more of Amherst Glacier here:

About the background graphic

This ‘warming stripe’ graphic is a visual representation of the change in global temperature from 1850 (top) to 2022 (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. 

Credit: Professor Ed Hawkins (University of Reading). Click here for more information about the #warmingstripes.

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