On 9.8.2019 we made the following observations at Grueben glacier:
Glacier
Since our visit in 2009, the glacier tongue has lost contact with the glacier. This was not clearly visible in 2018 due to the snow situation.
Grueben glacier on 9.8.2019.
Legend:
- Inside the yellow dots: Grueben Glacier
- Inside the orange dots: Dead ice cone
Summits: Gross Diamantstock, 3161m (left) and Hiendertelltihoren, 3179m (right).
Not much is left of the Grueben glacier.
Snow situation
Above 2700m a.s.l. the Grueben glacier is still covered to approx. 60% with snow.
Dead ice in front of glacier
The volume of the dead ice below the Grueben glacier is currently much larger than the volume of the glacier itself. The dead ice will gradually melt.
Grueben glacier: Dead ice on 9. August 2019.
The dead ice has a hilly surface (see also photo in the section above) and is covered with a lot of boulders. The large ice formation consists of several dead ice cones.
Grueben glacier: Hilly surface of dead ice on 9.8.2019.
The highest elevation is between 40 and 50m high (estimate), while in the valleys the ice thickness at the lowest points is probably > 5m (estimate). The dead ice still covers an area of approx. 900 x 600m (measured from an aerial photograph of approx. 2018).
Glacier gate
A glacier gate has formed in the northeastern dead ice cone.
Grueben glacier: Glacier gate on 9.8.2019.
The view inside the dead ice is currently still blocked by the pieces of ice lying in front of the glacier gate.
Dimensions of the glacier gate: width approx. 20m, height approx. 8m (both estimates).
Rockfall
On the day of our visit to the Grueben glacier the zero degree limit was 4500m and in the lowlands temperatures of up to 33° prevailed. So it was not surprising that we could watch falling rocks and boulders at the front of the dead ice.
Large rock slips from the edge of the dead ice front into the depth.
Credits: Daniela Oberli.
Stones also came loose from the northern lateral moraine.
Glacier forefield
The glacier forefield is characterized by countless boulders, which have experienced the same fate as the boulder shown above.
Grueben glacier: Glacier forefield on 9.8.2019.
Around the countless boulders meltwater also flows in countless smaller and larger watercourses towards Gruebensee. The meltwater transports very fine sediment, which is deposited to be formed by the water in an artistic way.
Grueben glacier: Sediment formed by water in the glacier forefield on 9.8.2019.
Sahara dust at Gruebensee
The 'sandy beach' was covered with snow until a few days ago. On the snow again Sahara dust had been deposited in spring. After the melting of the snow the Sahara dust formed different forms on the 'native' sand.
Grueben glacier: Sahara dust deposited on sand on 9.8.2019.
Vegetation
The vegetation of the glacier forefield is still quite sparse.
In the glacier forefield we could discover the following plants several times with increasing distance from the glacier:
Moss in the forefield to the Grueben glacier on 9.8.2019.
Grasses in the forefield of Gruebengletscher on 9.8.2019.
Saxifraga stellaris in the forefield of Gruebengletscher on 9.8.2019.
Cerastium latifolium in the forefield of Gruebengletscher on 9.8.2019.
Veronica alpina in the forefield of Gruebengletscher on 9.8.2019.
Oxyria digyna in the forefield of Gruebengletscher on 9.8.2019.
Leucanthemopsis alpina in the forefield of Gruebengletscher on 9.8.2019.
Algae in the glacier stream in front of the Grueben glacier on 9.8.2019.
Linaria alpina ssp alpina and small bush in the forefield of the Grueben glacier on 9.8.2019.
Credits: Daniela Oberli
Saxifraga bryoides in the forefield of Gruebengletscher on 9.8.2019.
Fauna
Before the glacier we could observe different insects:
Grueben glacier: White-tailed bumblebee (Lat.: Bombus lucorum) on boulder in the glacier forefield on 9.8.2019
Grueben glacier: Eristalis tenax on bloom in the glacier forefield on 9.8.2019
Grueben glacier: Brachycera on flower in the glacier forefield on 9.8.2019
Further we could observe in the glacier forefield:
- Numerous butterflies of the species 'Small tortoiseshell'.
One of them made a stop on the moss and had a snack.
- More butterflies. 2-3 varieties, all clearly less numerous.
- Traces of ibex and/or chamois in sandy soil.
- Div. spiders. One of these spiders crossed a small watercourse at very high speed.
The food supply for birds is probably still too low.
Special
In the transition at Gruebensee we discovered this small spruce at an altitude of about 2340m.
Grueben glacier on 9.8.2019.
Right next to it is an equally small juniper bush.
Published:
17.08.2019