Glacier Repeat Photography A Bear Glacier, Alaska, USA story
Glaciers
Water
USGS uses repeat photography of glaciers to quantify changes in glaciers over time. Repeat photography is a technique in which a historical photograph and a modern photograph, both having the same field of view, are compared.
For example, oblique aerial photographs of Bear Glacier were taken facing north and show glacial retreat along with icebergs floating in Bear Glacier Lagoon.
Photographs taken from the ground look north and were from the same location on the eastern part of the terminus of Bear Glacier. In the 96 years between photographs, Bear Glacier has retreated more than 3 kilometers (1.9 miles) and thinned by as much as 200 meters (656 feet). Only a very small part of Bear Glacier is visible from this location today, and the terminus is obscured by the trees.
Location
Aug. 10, 1976, Landsat 2 (path/row 74/18) — Bear Glacier, Alaska, USA
June 18, 1984, Landsat 5 (path/row 69/18) — Bear Glacier, Alaska, USA
Sep. 27, 1994, Landsat 5 (path/row 68/18) — Bear Glacier, Alaska, USA
July 1, 2000, Landsat 7 (path/row 68/18) — Bear Glacier, Alaska, USA
Aug. 5, 2001, Landsat 7 (path/row 68/18) — Bear Glacier, Alaska, USA
June 21, 2005, Landsat 5 (path/row 68/18) — Bear Glacier, Alaska, USA
July 21, 2007, Landsat 7 (path/row 68/18) — Bear Glacier, Alaska, USA
Sep. 15, 2010, Landsat 7 (path/row 68/18) — Bear Glacier, Alaska, USA
Sep. 2, 2014, Landsat 8 (path/row 68/18) — Bear Glacier, Alaska, USA
Sep. 4, 2018, Landsat 8 (path/row 69/18) — Bear Glacier, Alaska, USA
Sept. 9, 2020, Landsat 8 (path/row 69/18) — Bear Glacier, Alaska, USA
Bear Glacier, Alaska, USA Additional Imagery & Stories
Bear Glacier Lagoon
Before 1950, the entire basin was covered by Bear Glacier and ended at a terminal moraine. By 1961, a small lake had formed, referred to as Bear Glaci...
Glacial Retreat
A stable glacier advances a little in the winter and retreats the same amount in the summer. Bear Glacier likely did this and gradually built up a ter...
Racing Stripes
Glaciers move slowly, but Bear Glacier seems to have racing stripes. Glaciers pick up dirt and debris from the rocks they pass. They deposit that mate...