World of Change: Columbia Glacier

Produced by the Space Telescope Science Institute’s Office of Public Outreach in collaboration with the NASA Earth Observatory (https://earthobservatory.nasa.gov/).

 
Story adapted from Image of the Day post by Shad O'Neel and Robert McNabb: https://earthobservatory.nasa.gov/world-of-change/columbia_glacier.php

(DESCRIPTION)

Text, World of Change. The Earth spins in space amidst twinkling stars. The Retreating Columbia Glacier, Alaska.

 

(SPEECH)

[GENTLE MUSIC]

 

(DESCRIPTION)

The sheer edge of a rocky glacier with a chunk separated and ice flows below floating on a river at its base, surrounded by mountain peaks. Columbia Glacier, Alaska, United States. Image credit: NASA U.S. Army Engineer Research and Development Center. 1986 to 2019. Alaska's Columbia Glacier flows down from the Chugach Mountains, into a narrow inlet of Prince William Sound. It is one of the most rapidly changing glaciers on Earth. Since the 1980s, the leading edge of the glacier --its terminus-- has retreated more than 20 kilometers. Ice packs float on the water backed by snowy mountain peaks. NASA, Jon Von Atta. During this time, the glacier has lost about half of its total thickness and volume. Icebergs that have broken off, or calved, from the glacier float in the Columbia Bay, south of the terminus. This mixture of icebergs, sea ice, and meltwater is known as ice melange.

 

An aerial view shows the West Branch and Main branch of the glacier as it melts into the river. These visible and infrared light images, captured by Landsat satellites, show how the glacier and the surrounding landscape have changed since 1986. Snow and ice appear bright turquoise. Vegetation is green. Clouds are white or light orange. And open water is dark blue. Exposed bedrock is brown, while rocky debris on the glacier's surface is gray. Mostly turquoise fades gradually to dark blue at the terminus of the glacier with ice melange just downstream of it. Images transition from 1986 annually show dark blue invading much of the inner glacier through the 90's, leaving a turquoise portion downstream. Snow takes over the surrounding mountains by 2000. Then in 2003, the glacier flips at the terminus point, with clear open water downstream now. In 2006 snow and ice consume much of the landscape and refreeze a large portion of the glacier. Ice melange stretches much farther along the river in 2008 and 2009.

 

In the early 2010s the terminus widens and recedes upstream, splitting the branches of the glacier in two by 2015.

 

The open water continues to invade until 2019 where the main and west branch are split far apart.

 

Comparisons of July 1986 and June 2019 show the glacier completely receded and taken over by open water.