Allalin glacier
| Allalin glacier | ||
|---|---|---|
 Allalin Glacier and Allalinhorn from the east (2010) |
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| location | Canton of Valais , Switzerland | |
| Mountains | Valais Alps Mischabel | |
| Type | Valley glacier | |
| length | 6 km (2010) | |
| surface | 9.68 km² (2004) | |
| Exposure | Nutrient area north, consumption area east | |
| Altitude range | 4190 m above sea level M. - 2601 m above sea level M. (2005) | |
| Ice volume | 0.91 ± 0.23 km³ (2004) | |
| Coordinates | 637 854 / 99 583 | |
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| drainage | Saaser Vispa , Rhone | |
The Allalin Glacier is the largest glacier in the headwaters of the Saaser Vispa , in the Valais Alps , near the southern border of Switzerland . In 1973 it was 6.5 km long with an average width of 1.5 km. Since then, it has retreated about 500 m as the glacier melted . In 2004 an area of 9.68 km² was determined. The glacier has the number B52 / 29 in the Swiss glacier inventory.
location
The Allalin glacier has its origin on the glaciated peak of the Strahlhorn ( 4190 m above sea level ). It flows to the northeast and finally to the east along the eastern flank of the Rimpfischhorn and the Allalinhorn . To the west, the glacier is connected to the Mellich glacier via the firn-covered Allalin pass ( 3564 m above sea level ) . The glacier tongue ends with a break in the upper part of the steep slope northwest of the dam of the Mattmarksee at about 2700 m above sea level. M. It feeds the Saas Vispa, which brings the water through the Saas Valley to the Rhone .
During the Little Ice Age from the 15th century to the beginning of the 20th century, the Allalin Glacier reached all the way down into the Saas Vispa valley and dammed a lake in the area of today's Mattmark reservoir. This lake broke out again and again through the glacier wall, which led to sometimes devastating floods in the Saas Valley. That is why many valley residents emigrated. According to the chronicles, the population was affected by 23 major floods between 1589 and 1850 alone. It was not until 1926 that the danger was largely averted when a tunnel to drain the lake water was driven through the rock on the eastern slope of the valley.
In its central part, which is now the lower area, the Allalin Glacier merged with the Hohlaub Glacier during the Little Ice Age . This smaller glacier lies below the summit of the Allalinhorn ( 4027 m above sea level ). The Hohlaub glacier is separated from the Allaling glacier by the Hohlaub ridge.
Ice falls
A new kind of danger arose when the glacier retreated from the valley floor and as a result the part of the glacier leading over the steep slope lost its stability. While the ice in the valley had previously stabilized the ice in the flank, the tongue hanging over the steep slope has since then tended to slide over the smooth plates (see photo). A catastrophe occurred on August 30, 1965 when, during the construction of the Mattmark Dam , an ice mass of around half a million cubic meters (two million cubic meters according to ETH Zurich) suddenly fell from the Allalin Glacier and spilled most of the construction facilities at the foot of the dam. 88 people were killed.
On 30./31. In July 2000, a similar ice fall occurred with a volume of about one million cubic meters. The crack was slightly higher than in 1965, this time there was no damage.
In the meantime, however, the tongue has melted so far that there is little ice left on the steep flank. If the current decline continues, in a few years the glacier will end in a flat and harmless tongue above the critical escarpment.
literature
- Françoise Funk-Salami: A glacier makes history . (PDF; 582 kB) In: Die Alpen , SAC magazine , 9/2001
Web links
- Interactive before and after comparison pictures of the Allalin glacier
- Map section swisstopo
- Allalin glacier on the ETHorama platform
Individual evidence
- ↑ a b c d Fluctuations of Glaciers Database. World Glacier Monitoring Service, Zurich 2013, doi: 10.5904 / wgms-fog-2013-11 ; Retrieved December 11, 2013
- ↑ a b Daniel Farinotti, Matthias Huss, Andreas Bauder, Martin Funk: An estimate of the glacier ice volume in the Swiss Alps. (PDF; 756 kB) In: Global and Planetary Change , 68, 2009, pp. 225-231.
- ↑ Firne and ice in the Swiss Alps, glacier inventory , ETH Zurich Geographical Institute, publication No. 57 Zurich 1976 page 86