February 11, 2010

Rotmoosferner Retreat and Dynamic Change

Posted by Mauri Pelto

There are currently 51 glaciers in the Ötztal Nature Park. Right now, glaciers cover 27% of the total area of the Ötztal Nature Park. All have been retreating, from 1987-2006. Detailed mapping of these glaciers and Rotmoosferner by Abermann and others (2009), University of Innsbruck provide interesting results. Ötztal glaciers lost 8 % of their total area. One of the glaciers that has a long record of observation is Rotmoosferner. This glacier has retreated 2.1 km since the Little Ice Age and 600 meters since 1969, 15 meters per year. A detailed map of Rotmoosferner from Abermann and others (2009) University of Innsbruck indicates that in 1975 it was joined to the Wasserfallferner, but in 2005 it separated. In the image above the Rotmoosferner is to the lower left and the Wasserfallferner above and to the right. Compare this image to one taken four years later at the end of the post. In the last decade new rock outcrops have emerged in the middle of the Rotmoosferner. These outcrops are noted in the google earth image below. The annotated image also indicates the former zone of connection to the Wasserfallferner. A map of the outline of the glaciers clearly identifies the new outcrops and the separation of the glaciers. The map is based on satellite imagery and older aerial photographic based maps by Abermann and others (2009) from 1969, 1997 and 2006. The retreat from 1969-1997 occurred across a relatively flat foreland. The current retreat is up a steeper slope, since 2001 retreat has averaged 18 m per year. The appearance of the rock outcrops in the mid-section of the glacier as the map shows, indicates little contribution to the tongue of the glacier, and that retreat of this lower section will continue to be rapid. The glacier still does appear to have an accumulation zone most years and is thus not forecast to disappear with current climate.
The picture below is from September of 2008 from Jakob Abermann, Institute of Meteorology and Geophysics, University of Innsbruck. Note the change versus the first picture from four years earlier. The exposed rock area has expanded amazingly and is nearly cutting off the lower tongue.