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What sets Gornergletscher apart from most other glaciers in the Alps other than ice-dammed Gornersee, is the presence of meltwater lakes on its tongue. Some reach impressive sizes, because some of the glacier ice is "cold" ice. Ice flowing down from the very high firn basins of Grenzgletscher, between Lyskamm and Monte Rosa, is somewhat colder than the pressure melting point. Thus, meltwater cannot drain through moulins, as on other glaciers.
Lake 1" near 627.500 / 91.200, panorama towards Monte Rosa (left) and Lyskamm (right), in between Grenzgletscher. The lake discharges through a meltwater channel towards the left.
Lake 1", panorama towards Breithorn (centre left) and Matterhorn (right). Dark cryoconite at the bottom of the lake formed ripple marks as a result of wave motion.
Meltwater channel, at "Lake 1"; prominent, near vertical foliation and strandline a few centimetres above the water level, showing a slight lowering of the lake level.
Close-up of the foliation at the edge of "Lake 1"
"Lake 2" near 625.300 / 91.500, panorama towards Klein Matterhorn and Unterer Theodulgletscher (far left), Matterhorn (centre) and Riffelhorn (right). Huge boulders have moved away from the medial moraine, and some have fallen towards the lake.
In the basin of "Lake 2", which drains through a deeply incised meltwater channel towards the left. Note fine sediments on the near side of the lake.
View over "Lake 2" towards Breithorn and Breithorngletscher. Note strandlines on the steep far shore of the lake. In spring the water level is higher, because the outflow becomes partially blocked during winter.
Close-up of "Lake 2" with ripple marks in the shallow water.
"Lake 2", aerial photo by Bernhard Edmayer, August 2006. During a cold spell a thin layer of ice has formed temporarily on the lake. On the upper left is the outlet of meltwater channel with a huge moraine block.
In addition to large meltwater lakes, there are countless small meltwater ponds. Because of the low ice temperatures, which prevent draining of the water, they reach much bigger dimensions than cryoconite holes on truly temperate glaciers.
The crescent-shaped outline of this pond is caused by the diurnal movement of the sun across the sky. The straight side of the half moon is on the southern side and runs in an east-west direction.
In some places thousands of ponds complicate travelling over the glacier. At the bottom of the ponds, small cavities form as a result of absorption of sunlight by dark sediment.
|Unless mentioned otherwise: Photos Jürg Alean, August 2004.|