Funnel-shaped surface depressions - Indicator or accelerant of rapid glacier disintegration? A case study in the Tyrolean Alps

The development of this 15 to 30 m deep depression was monitored with a combination of methods in high detail, including direct ablation measurements and a time series of seven high-resolution airborne laser DEMs, plus recordings of ice flow velocity and surface elevation with DGPS. The thickness of ice and sediment layers was measured with vibroseismic soundings in 2012 and 2013. Similar developments were observed at three other glaciers with extreme retreat rates. Our investigation suggests that this mechanism has a major impact on and can be read as an indicator of a nonlinear increased response of glaciers to climate change.