Swiss Alps - Environment and Climate - Climate Zones

Climate Zones

As the temperature decreases with altitude (0,56°C per 100 metres on yearly average), three different altitudinal zones, each having distinct climate, are found in the Swiss Alps:

• Subalpine zone

The Subalpine zone is the region which lies below the tree line. It is the most important region as it is the larger of the three and contains almost all human settlements as well as the productive areas. The forests are mainly composed by conifers above 1,200-1,400 metres, the deciduous tree forest being confined to lower elevations. The upper limit of the Subalpine zone is located at about 1,800 metres on the north side of the Alps and at about 2,000 metres on the south side. It can however differ in some regions such as the Appenzell Alps (1,600 metres) or the Engadin valley (2,300 metres).

• Alpine zone

The Alpine zone is situated above the tree line and is clear of trees because of low average temperatures. It contains mostly grass and small plants along with mountain flowers. Below the permafrost limit (at about 2,600 metres), the alpine meadows are often used as pastures. Some villages can still be found on the lowest altitudes such as Riederalp (1,940 m) or Juf (2,130 m). The extend of Alpine zone is limited by the first permanent snow, its altitude greatly vary depending on the location (and orientation), it is comprised between 2,800 and 3,200 metres.

• Glacial zone

The glacial zone is the area of permanent snow and ice. When the steepness of the slope is not too high it results in an accumulation and compaction of snow, which transforms into ice. The glacier formed then flows down the valley and can reach as far down as 1,500 metres (the Upper Grindelwald Glacier). Where the slopes are too steep, the snow accumulates to form overhanging seracs, which periodically fall off due to the downwards movement of the glacier and cause ice avalanches. The Bernese Alps, Pennine Alps and Mont Blanc Massif contain most of the glaciated areas in the Alps. Except research stations such as the Sphinx Observatory no settlements are to be found in those regions.