Glaciers in the high mountain regions of the Himalayas offer a different picture to our Alpine glaciers: many of them are completely covered in debris, and many areas are overlooked by steep ice walls – vertical cliffs up to 30 metres high. From a distance, this makes the glacier surface look like the warty skin of a toad.
Glaciers in the high mountain regions of the Himalayas offer a different picture to our Alpine glaciers: many of them are completely covered in debris, and many areas are overlooked by steep ice walls – vertical cliffs up to 30 metres high. From a distance, this makes the glacier surface look like the warty skin of a toad.
Researchers had previously assumed that the insulating debris protects the ice from direct solar radiation, thereby slowing down the melting of the underlying ice. However, satellite measurements show that debris-covered glaciers in the Himalayas might lose mass as quickly as debris-free glaciers.
Multiple studies suggest that ice cliffs could be responsible for a large part of the high volume loss, as alongside the insulating debris, another characteristic feature of high-altitude Himalayan glaciers is steep ice walls up to 30 metres high. Researchers now suspect that these ice cliffs convey large quantities of atmospheric heat into the ice and so contribute to glacier melt.
As part of an international research project, former ETH doctoral student Pascal Buri went to the Langtang Valley in Nepal and used a computer model to closely examine the formation and decline of ice cliffs and their influence on the melting of debris-covered glaciers. The study has just been published in the journal PNAS.
Read more at ETH Zurich
Image: Ice cliffs are a typical feature of Himalayan glaciers. (Credit: Pascal Buri / ETH Zurich)
