(per) The Gurschen glacier in Canton Uri is sweating–and melting. Each summer a little more. Each year, before the start of the winter season, the company that runs the Gemsstock railway has to re-build the ramp, which leads from the mountain station to the ski piste on the glacier. This reconstruction is time consuming and very expensive; 3,000 litres of diesel and many man-hours, up there at 3,000 metres above sea level–every year.

Scientific experiment

However, this drudgery is to find a provisional solution. In May the mountain railway companies of Andermatt (1) covered the higher reaches of the Gurschen glacier and the bordering rocks with 2,500 square metres of white fleece, creating a kind of folie à la Christo. It is the first such attempt in Switzerland and the people responsible hope that the ice will stay cool enough to preserve the ramp. Within the framework of a scientific experiment, the Section of Glaciology at the Laboratory of Hydraulics, Hydrology and Glaciology at ETH Zurich (VAW) is involved in the "packaging" of the glacier. Below, at the foot of the ramp, on a small plateau, glaciologist Andreas Bauder covered a trial area with the same material, in order to measure the effectiveness of the cover.

Lower melting rate

Preliminary results are encouraging for the railway company but a bad sign for the climate. The fleece is doing its job and has prevented the perpetuated snow and ice from disappearing at the same rate as hitherto. Only around 30 centimetres of the mass of the ramp under the cover has melted. In fact, ETH researchers measured a truly striking difference of 150 centimetres between the control area and the part of the glacier that is not covered.

In September the railway company will remove the fleece. Next spring, after the end of the skiing season, the glacier is to get its summer coat back. Bauder wants to continue the data series, perhaps even extend it. "The railway company realises that this experiment needs to run for a number of years, also because of the variability of the weather," says the glaciologist.

On Gemsstock at 3,000 metres above sea-level, a gigantic piece of fleece protects the ski ramp, which consists of ice and perpetuated snow. ETH glaciologists measure the loss of thickness (Picture: Andermatt Gotthard Sportbahnen AG). large

Glacier tables support preservation

That the packing trial would work was something that Bauder had not doubted. "Covering the ice so that it doesn't melt, isn't really something new." The phenomenon of glacier tables is proof that a cover hinders the shrinkage of perpetuated snow, says the researcher. Glaciologists use the term glacier table to describe a big flat stone area that lies on a base of perpetuated snow and ice. These stones protect the underlying ice below from localised rays. Around them, however, where the sun shines directly on to the glacier, the level of ice sinks.

Nevertheless, Bauder realises that the problem of shrinking glaciers cannot be solved with fleece covers. "For me it was interesting to see how our research can be applied in practice," he says. In Switzerland the climate has been getting warmer for the past 150 years and the glaciers have lost a lot of mass. This conclusion is borne out by the results of the Swiss Glacier Monitoring Network (2). For the past 20 years the thickness of the Swiss ice streams has shrunk, on average, by a metre each year.