Himalaya, Khumbu region

General Information

Khumbu Glacier with ice pinnacles below the Icefall. The west ridge of Mt Everest is on the left, and Nuptse rears overhead. Photo: Matt Westoby.

The Himalaya, together with the Karakorum and Hindu Kush, form the greatest mountain range on Earth. These mountains form an immense physical barrier, separating the countries of the Indian subcontinent from the high plateau of Tibet. The Himalaya themselves stretch for 2500 km through Pakistani-administered Kashmir, through northern India, Nepal, Bhutan and Tibet (China). With many mountains exceeding 7000m, culminating in Everest (8848m), much of the region is covered by glacier ice. Although many glaciers are remote and inaccessible, they are a vitally important source of water to the bordering countries, especially during the growing season. The water locked up in glaciers at high altitude has given rise to the expression “water tower of the world”. Indeed, it is estimated that 2300 million people depend on Himalayan glaciers and snow-melt for their water supply. This important water resource has potential for hydro-electric power generation, although, as yet, this is little developed. On the negative side, glacier recession is resulting in an increase in glacier hazards, notably the failure of growing moraine-dammed lakes. Catastrophic ‘glacial lake outburst floods’ (GLOFs) occur at irregular intervals.

This collection of images focuses on the Mt. Everest region of Nepal, covering several glaciers in the Khumbu and Imja valleys. Mt Everest is also known in Nepali as Sagarmatha and in Tibet as Chomolungma, and of course is the focus of considerable attention from mountaineers, thrill-seekers and scientists. Our project (in 2003) involved the investigation of the surface glaciology, glacial geology and geomorphology of the region, with most emphasis on the Khumbu Glacier, alongside and across which is the main trekking route to Everest Base Camp. Project members were from Aberystwyth University (Michael Hambrey, Neil Glasser, Duncan Quincey) and Reynolds Geosciences Ltd. (Shaun Richardson) and funding was provided by the Teaching Company Scheme (TCS) and Aberystwyth University.

This collection has been assembled to support an Exhibit by several universities at the Royal Society’s Summer Science Exhibition, 30 June - 5 July 2015. More information can be found about Himalayan glaciers in our book «Gletscher der Welt» (Haupt AG, 2013).

Map of our field area, noting the main glaciers and significant peaks in the Khumbu and Imja valleys.

Satellite image of the Everest region, highlighting debris-mantled glaciers and their Little Ice Age moraines (see map for locations). This Landsat OLI scene was taken on 10 October 2013 for the United States Geological Survey. Image prepared by Duncan Quincey (University of Leeds).

Key attributes of the four glaciers we investigated in 2003.

Khumbu Valley

The Khumbu Valley runs west from Mount Everest to the villages of Pheriche (4240 m) and Dingboche (4358 m), where a large moraine complex from the Last Glacial Maximum marks the junction with the Imja Valley. This valley is the main route for trekkers and mountaineers intending to reach Everest Base Camp and the summit respectively. The upper part of the valley is a snow-and ice-filled avalanche-prone basin that represents the main accumulation area of the Khumbu Glacier. It was named the Western Cwm (Cwm = Welsh for valley) by pioneering pre-WW2 mountaineers looking down from Everest’s high ridges. From here, ice flows over the infamous Khumbu Icefall, where many Sherpas and mountaineers have perished. Just below the icefall is Everest base camp, which was devastated in the May 2015 earthquake. This is the final destination of most trekking groups. Next follows the low-gradient Khumbu Glacier tongue, characterized by ice pinnacles in its upper part, and debris cover and ponds in the lower part. This was the site of our research investigations. A large end moraine over 100 m high marks the terminus of Khumbu Glacier, down which a small outlet stream flows to the valley floor below. The lower Khumbu Valley is a broad glacial trough with prominent lateral moraines and a flat bottom, with debris-covered Chola Glacier extending from the peak of Taboche to the valley floor. Areas of grassland provide opportunities for grazing. The village of Pheriche has medical facilities, especially geared up for dealing with altitude sickness. Dingboche, being on the main trekking route, has a range of accommodation.

Digital elevation model (DEM) image drapes for lower Khumbu Glacier (see map). The tongue is debris-mantled almost up to the Khumbu Icefall below which blue glacier ice is exposed. The source DEM data are provided by SRTM and the images themselves were acquired by ALOS AVNIR on 24 October 2008. Image prepared by Duncan Quincey (University of Leeds).

Imja Valley

The Imja Valley runs east-west from the peak of Buruntse (7220 m), with Lhotse (8501 m) on the north flank and Ombigaichen (6243 m) and Ama Dablam (6856 m) on the south side (see map above). At the head of the valley is Imja Glacier with its tributary Lhotse Shar, which terminates in a rapidly expanding moraine-dammed lake, Imja Tsho. The moraine dates from the Little Ice Age, and is ice-cored in parts, but some well-vegetated outer ridges could be older. This lake has only developed in the last two decades, and is now 2km long. According to some scientists, there is potential for the moraine dam to fail, triggering a “glacial lake outburst flood” (commonly referred to as a GLOF), but our research published in 2008, and that of a Japanese team in 2009, suggested that the dam was relatively stable. More recently (2011), the International Centre for Integrated Mountain Development in Kathmandu, produced a report on GLOF hazards, and also concluded the Imja Tsho was probably not dangerous in the short term, but should be closely monitored.

However, concern remains, to the extent that the United Nations Development Programme is funding a remediation project to lower the lake level. The April M7.8 and May M7.3 earthquakes have caused terrible loss of life and devastation in Nepal. There is now concern that in general (a) moraine dams that were considered safe have become seriously weakened, and (b) that the lakes are more vulnerable to avalanches and rockfalls, potentially causing displacement waves and breaching the dams. A study of the impact of the earthquakes on glaciers and moraine-dammed lakes is therefore a pressing need, in order to assess the vulnerability of downstream communities to new hazards.

Digital elevation model (DEM) image drapes for Imja Valley (see map). Moraine-dammed Imja Tsho (lake) is prominent, beyond which is Imja Glacier. The Lhotse glaciers are in front and to the left, and the Ombigaichen-Ama Dablam glaciers to the lower right. The source DEM data are provided by SRTM and the images themselves were acquired by ALOS AVNIR on 24 October 2008. Image prepared by Duncan Quincey (University of Leeds).

The south face of Lhotse is some 3000 m high, and at its foot is the debris-covered Lhotse Glacier. Its Little Ice Age moraine is breached in a few places, but there seems to be no danger of water build-up in this case.

Opposite the snout of Lhotse Glacier is the much smaller Chuckhung Glacier, fed by the steep faces west of Ombigaichen. Chuckhung Glacier created a deep moraine-dammed lake, which suffered a breach on an unknown date prior to the first satellite imagery of 1962. There is no record of any damage from the resulting GLOF, but the debris fan (measuring 300 x 100 m) and large dislodged boulders beneath are impressive. The old lake floor displays a wide range of sedimentary types.

Another debris-mantled glacier flows from Ama Dablam. This glacier is characterised by multiple sets of moraines. The valley continues west below Ama Dablam and is joined by the Khumbu Valley just below the village of Dingboche, where moraines from the Last Glacial Maximum are developed.

In addition to illustrating the above features, roughly in a down-valley direction, we also show features outside the Little Ice Age moraines, including the river-bed, a lateral morainic trough and a rock glacier. We also show some aspects of camp life.

The Imja Valley is reached by an easy path from Dingboche, although much less frequented than the Khumbu route. The main attraction for “trekkers” is Imja Tse (also known as Island Peak, c. 6160 m), but this involves climbing on rock and ice/snow (grade Alpine PD+), so is only suitable for mountaineers.

Himalaya, Khumbu region

General Information

Khumbu Valley

Imja Valley

Further reading