High alpine habitat

A wealth of exciting phenomena

At first sight, this high alpine landscape appears to be completely barren, but if we take a closer look a host of fascinating phenomena are revealed.

Dominated by weather and erosion, this barren habitat demands maximum adaptablity from both plants and animals.
Here, in between the flower meadows and the highest mountain tops, stones and rocks dominate the landscape. Jagged rock edges stand out against the sky, whilst enormous debris chutes descend towards the valley.

In the upper alpine zones the mighty forces of erosion are predominant. The sparse vegetation is unable to hold back the soil. Blocks of rock, broken up by the tremendous force of freezing water, crash down towards the valley floor, forming gigantic slopes of scree.

Debris chutes are a common sight in the National Park. This is due to the type of rock, dolomite. The majority of this brittle rock is eroded into great boulders, which in turn break up, constantly adding to the vast slopes of scree at the base of the rock face.

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Wind and Weather

No other habitat is so much exposed to wind and weather as the high alpine zone.

Extreme temperatures and strong winds push plants and animals to the limit.

In the upper alpine zone, the average temperature throughout the year is 0°C or less. Minimum and maximum temperatures vary between –40 and +60°C! Strong winds increase the cooling factor. Snow, however, provides excellent insulation against the cold, but in exposed locations it is generally blown away rapidly.

The dry climate and barren dolomitic soil do not provide ideal conditions for plant life in the upper alpine zones of the National Park.

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Permafrost

Whereas specialists have been studying this phenomenon for years, it is only now that society in general is becoming aware of its importance.

At an altitude of approx. 2400m on slopes in the shade and 2800m on sunny slopes, the ground in the National Park  remains frozen all year round. Only the surface layers, to a depth of 1 to 2 metres, thaw during the summer. Permafrost cannot be seen from the surface so that often one is not even aware of it.

In connection with global warming, greater importance is now being attached to the phenomenon of permafrost. The stability of slopes where permafrost is beginning to thaw can no longer be guaranteed, which poses a threat of mudslides for zones of habitation. For this reason, certain villages, for instance the Upper Engadine resort of Pontresina, have built special dams in order to minimise this danger.

Marmots seem to know where the permafrost begins and never build their winter burrows there. Such a location would be unsuitable, as temperatures in their winter burrow should never drop below freezing.

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Blockgletscher Val Sassa

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Rock glacier

Rock glaciers, also called stone flows, creep slowly downhill, driven by gravity.

Unlike ice glaciers, rock glaciers consist mainly of frozen rock detritus with ice in the cavities between. With the force of gravity, these fascinating formations creep steadily downward, moving as much as a half a metre per year.
In summer the ice in the upper 1 to 2 metres of the rock glacier thaws. At this time of year, the noise of the melting water can be heard not far below the surface.
The Chamanna Cluozza–Fuorcla Val Sassa–S-chanf walk leads past the nearly 2 km-long Val Sassa rock glacier.

► Here you will find a summary of the effects of climate change on nature in the Swiss National Park (in German).

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Creeping soils

One of the most spectacular sights in the high alpine zones are the slow moving creeping soils, splaying out like tongues across the slopes.

These drop-shaped rings form when the surface layers of the soil thaw; as they become waterlogged, they ooze downhill over the still frozen subsoil. This process is called solifluction. Unlike rock glaciers, creeping soils are not necessarily linked with permafrost. Creeping soils are common in the National Park between 2300 and 2700m altitude.

Depending on the steepness of the slope, active creeping soils move several centimetres downhill per year. Inactive creeping soils are generally more covered by vegetation than active creeping soils.

In the region between Munt Buffalora and Munt la Schera (route 15) there are a number of partially active creeping soils. These unusual landscape elements are the subject of scientific research.

► Here you will find a summary of the effects of climate change on nature in the Swiss National Park (in German).

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