Yakutat Retreating

NASA Earth Observatory image by Robert Simmon, using Landsat data from the U.S. Geological Survey.

Located in the Brabazon Range of southeastern Alaska, Yakutat Glacier is one of the fastest retreating glaciers in the world. It is the primary outlet for the 310-square mile Yakutat ice field, which drains into Harlequin Lake and, ultimately, the Gulf of Alaska. The Operational Land Imager on the Landsat 8 satellite captured this image of the glacier and lake on Aug. 13, 2013.

Snow and ice appear white and forests are green. The brown streaks on the glaciers are lateral and medial moraines. During the past 26 years, the glacier’s terminus has retreated more than three miles. What is causing the rapid retreat? University of Alaska glaciologist Martin Truffer and colleagues pointed to a number of factors in their 2013 study published in the Journal of Glaciology. The chief cause is the long-term contraction of the Yakutat Ice Field, which has been shrinking since the height of the Little Ice Age. As other nearby glaciers retreated, Yakutat ice field was cut off from higher-elevation areas that once supplied a steady flow of ice from the north. With that flow cut off, there simply is not enough snow falling over the low-elevation Yakutat ice field to prevent it from retreating.