A supraglacial moraine is spoken of when the surface of a glacier is covered with debris and/or boulders.
A supraglacial moraine can cover a glacier completely or only partially in the area of the glacier tongue. The photos below show different variants.
1) Unteraar glacier
The Unteraar glacier is one of the largest glaciers in the Alps, which has a pronounced supraglacial moraine.
30.6.2018: View of the pronounced supraglacial moraine of Unteraar glacier.
2) Breithorn glacier (Lauterbrunnen valley)
In the area of the tongue, the Breithorn glacier, like the Unteraar glacier, is covered with debris over its entire width. The photo shows that the glacier to the right of the glacial lake is not covered by debris.
20.9.2018: View of the supraglacial moraine of the Breithorn glacier (Lauterbrunnen valley).
3) Grüebu glacier (Saas Valley)
The photo of the Grüebugletscher shows how an supraglacial moraine is formed. The massif on the right (Inner Rothorn, 3454m) is very fragile. Due to erosion, rocks, rockfalls and smaller landslides regularly fall onto the glacier. The flow of the ice slowly transports the boulders, debris and rubble towards the valley.
9.8.2020: View of the supraglacial moraine of the Grüebugletscher (Saas Valley).
The lowest part of the Grüebu glacier is so thickly covered with boulders and debris that it is no longer clearly visible where the glacier ends.
9.8.2020: View of the supraglacial moraine of the Grüebu glacier (Saas Valley) in the area of the tongue.
The tongue extended approximately to the orange dots on 9.8.2020.