Glaciers
and water

Glaciers are formed where the summer temperatures are not sufficient to melt the snow that had fallen in the winter. Year after year, layers of snow fall one on top of the other. The snow transforms to firn and then later to ice thanks to the pressure, this slow moving mass moves gradually to the valley as a result of gravity. Areas where more snow falls in winter than can melt in summer are called accumulation zones. The area where ice melts from the lower lying glacier tongue is called the ablation zone. Depending on location, a distinction is made between cirque, hanging and valley glaciers.

Accumulation zone - Equilibrium line - Ablation zone

During the ice ages, the Alp glaciers had far greater coverage than they do today. The ice has abraded the once V-shaped valleys to the wider U-shaped trough valleys prevalent today. You can still see today how the glaciers over the course of millions of years have shaped and changed the Hohe Tauern region by the many cirques and valleys. The typical pyramid-formed peaks – such as that of the Grossglockner – have emerged from cirque glaciers and are sometimes referred to as glacial horns in their most extreme form. 

The Pasterze glacier at the Grossglockner has an estimated 16 square kilometres of area and a glacier tongue of four kilometres in length making it the largest glacier in the Eastern Alps. Since 1879, the change in the Pasterze's length is measured annually. From 2006 to 2016, the glacier tongue shrank by approximately 40 metres each year. The Eastern Alps were repeatedly marked by glacial advances and retreats. Thousand year old stone pine trunks found in the vicinity of the Pasterze indicate that trees grew in the area of today's glacier tongue over 10,000 years ago.

Annual glacier reports:
After a call for action by the Austrian Alpine Club, measurements of Austrian glaciers have been recorded for the past 125 years. The results of these measurements are published by the Austrian Alpine Club annually on its website. (www.alpenverein.at)

Climate change has drawn attention to another phenomenon in the summit regions: Ice in the ground has held rock and scree together like cement for thousands of years. If the ground has a temperature of minus three degrees Celsius all year round, this is called permafrost. Areas where permafrost melts as a result of climate change, find that boulders will suddenly become unstable. One example is the Sattelkar in the Obersulzbachtal (Obersulzbach valley) or the rock glacier in the Dösental (Dösen valley).

The Hohe Tauern National Park is the reservoir of the Alps: There are 279 streams and rivers, of which 57 are fed from glaciers and are characterised daily and seasonally by the respective volume of meltwater. Examples of waterfalls where water plunges over cliffs into the deep with impressive force include Krimmler Wasserfälle (Krimml waterfalls), Umfalfälle (Umbal waterfalls) in East Tyrol and Gössnitzfall (Gössnitz waterfall) in Carinthia. Following the retreat of the ice, an estimated 500 mountain lakes were formed in the Hohe Tauern cirques that resemble sparkling jewels in the high mountain landscape.