January 28, 2012
The Hallstatter Glacier (also sometimes called Dachstein Glacier along with the Gosau Glacier) is on the north slope of Dachstein an area of heavy recreational use. The result is good photographic records of glaciers change. This record combined with a recent cooperative project between University of Innsbruck, Blue Sky Weather Analysis and Energie AG Upper Austria provides a good snapshot of glacier change in northern Austria. The glacier begins at 2800 meters and descends to 2200 meters, image below from University of Innsbruck. This project has compiled the annual terminus change of the glacier from 1950-2007, in the image below. The retreat from 1950-1975 averaged 8 meters per year. A period of minor readvance from 1977-1991 occurred, followed by increasingly rapid retreat from 1992-2007 averaging over 10 meters per year in the last decade. Total retreat has been 350 meters from 1950-2007. Over the last century the change is chronicled in the two images, 1900 and 2007, from the Dachstein Project and the 2009 margin is traced in a Google Earth Image, blue line. This project was undertaken because of the importance of the glacier runoff to hydropower production along the Traun and Gosau Watersheds in particular. The change in terminus via mapping from 1969-2002 is evident in the Innsbruck image (2002), the Google Earth image is from 2009. There is thinning particularly of the width of the two main terminus tongues.The mass balance of the glacier has been measured since 2007, every year has had negative balances. In 2011 the snowline was again high, snowpack very limited at the end of the melt season which persisted into October. An Ikonos image from October 2, 2011 indicates that 30-35 percent of the glacier is snowcovered, this is the AAR and it needs to be at 60 for equilibrium.