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Alpine snow and water resources in a changing climate


Although Switzerland is regarded as the reservoir of Europe, it cannot be relied upon to deliver the right amount of water in the right place at the right time. Under the influence of climate change, such variances will become even more pronounced in future. Various research groups at the WSL and SLF are investigating hydrological and climatological issues, and in particular the relationships that exist between snow, runoff, climate and natural hazards.

Natural snow cover acts as a giant water reservoir, supplying water well into summer, and ensuring that hydro-electricity can then still be produced. We develop models to estimate how much water is stored in the snow and thus how much melt water is likely. These models are also useful in assessing the impact of climate change on the hydrological system. They yield valuable information that not only helps the electricity industry make decisions, but also helps to improve forecasts of spring flooding.

Permafrost : permanently frozen ground

Permanently frozen ground or permafrost covers around 6% of the Swiss Alps and occurs primarily above 2400 m. Permafrost can consist of all kinds of frozen ground (rock, scree slopes, moraines etc). Since 1996, boreholes have been drilled and fitted with measurement instruments in more than twenty permafrost locations in the Swiss Alps. The SLF permafrost measurement network supplies essential data on the state of the permafrost and aids the understanding of the complex interaction between the ground surface and underlying substrates.

Snow as a natural hazard

Among the core activities of the WSL, serving the purpose of safeguarding the population against natural hazards in the long term, is the research it conducts in the disciplines of avalanche formation, dynamics and protection. An already thorough understanding on how avalanches are formed enables the SLF to publish reliable alert bulletins. This way, safety personnel of ski resorts and mountain villages as well as winter tourists and free riders are warned against impending danger. However, more research is required to find out exactly when and where an avalanche is triggered.

All the information on avalanche research and prevention can be found under the research topic “Natural hazards”. For an overview of the current snow and avalanche situation, please check

Snow as a substance

Snow is a porous material composed of ice and air which undergoes constant change due to external influences. Even for porous materials with non-mutable microstructures, science provides only very limited theories about the relevant mechanical and thermal properties. To analyse the microstructure of snow, therefore, special experimental and theoretical concepts are required. Only in this way can any progress be made in avalanche forecasting and climate research.

The core topic of the team "Snow Physics" is structure and property of snow and firn at different scales. Research is done in a cold laboratory with micro-computed tomography (micro-CT), nature-identical snow production and our in-house designed snow-breeders as well as in the field with natural snow.

Snow – an important resource for winter tourism

Because of its winter tourism, Switzerland is extremely dependent on snow. Snow depth measurements are therefore used not only for avalanche warning purposes, but also to examine the influence of climate warming on the snowpack.

In order to quantify such changes and correctly classify individual winters with very little or large amounts of snow, long-term serial studies are very important. Together with MeteoSwiss, the SLF maintains a network of more than 100 observers who measure the fresh snow and overall snow depths daily from October to May. he majority of these long-term serial measurements date back around 50 years, but individual stations have been taking measurements for more than 100 years.

WSL also participates in cooperative commercial projects like energy saving production of technical snow, conserving snow over the summer and the efficient preparation of ski slopes. Also, we conduct in-depth studies on the complex system “man – sliding material – snow”.