Automatic weather stations at the Yala Glacier Base Camp
Photo: Tika Gurung/ICIMOD

Spanning 5,170 to 5,750 metres above sea level (masl), Yala Glacier in Langtang Valley, Rasuwa District, is one of the main research sites on which cryosphere experts from the International Centre for Integrated Mountain Development (ICIMOD) carry out biannual mass balance measurements. The glacier is used for conducting training on field based cryosphere activities as well. ICIMOD has been conducting research on the glacier since 2011. The most recent spring expedition was carried out from 16 April 2017 to 28 April 2017.

Getting equipment ready before heading out to Yala Glacier Base Camp
Photo: Dorothea Stumm/ICIMOD

Research Associates Tika Gurung (L) and Gunjan Silwal (R) test the portable steam driven ice drill used for drilling holes in glaciers to install bamboo stakes. The steam drill weighs about 14 kilograms. Its light weight makes it easy to carry over long distances and convenient for drilling holes in glaciers for various purposes. It is easy to operate, even for a single person.

Drilling ice to install stakes on the glacier
Photo: Tika Gurung/ICIMOD

Unlike manual drilling which produces ice debris and needs to be cleared repeatedly, drilling with the steam drill is very efficient. The drill consists of a boiler for water which is heated with gas. Once it is ready, steam is released through a pipe with a nozzle which is placed on the surface of a glacier. The ice melts as latent energy from the steam is released and the nozzle and pipe drill into the glacier.

Stake drilling in difficult weather
Photo: Dorothea Stumm/ICIMOD

Deteriorating weather such as heavy snowfall make work harder for glaciologists and can affect mass balance measurements. This picture was taken on 24 April 2017, a day of heavy snowfall. Glaciologists often have to work in such conditions as their task is time bound.

Stake installation at lower elevation
Photo: Maxime Litt

Bamboo stakes are installed along the glacier profile to measure mass gain and loss over a large elevation range. Eight measurement sites on Yala Glacier have been maintained since 2011 and five newer sites have been established to prepare for a time when older sites become obsolete because of glacier shrinkage.

Surveying stake location using DGPS
Photo: Pasang Sherpa/Glacier Safari Treks

Tika Gurung, Research Associate, surveying stake location using a differential geographical positioning system (dGPS). dGPS is used to get a precise measurement of the stake location, which allows for the calculation of the flow velocity of the glacier.

Getting the precise location and elevation of each stake
Photo: Dorothea Stumm/ICIMOD

During the 2017 spring expedition, dGPS measurements were carried out at each stake to get precise location and elevation data. Glacier mass balance depends very much on altitude because elevation dependent temperature is one of the governing factors of the mass balance.

Maintenance work on AWS
Photo: Tika Gurung/ICIMOD

During the 2017 spring expedition, dGPS measurements were carried out at each stake to get precise location and elevation data. Glacier mass balance depends very much on altitude because elevation dependent temperature is one of the governing factors of the mass balance.

Reprogramming temperature sensors
Photo: Dorothea Stumm/ICIMOD

Wireless reprogramming of temperature sensors that were deployed on Yala Ridge in May 2014. The sensors measure ground surface temperatures (GST) and indicate the possible occurrence of permafrost deeper underground.

A typical end to a long day on the glacier
Photo: Dorothea Stumm/ICIMOD

Returning to Yala Glacier Base Camp after installing stakes and digging snow pits on the glacier.

Locating temperature logger sensors
Photo: Dorothea Stumm /ICIMOD

Gunjan Silwal locating temperature logger sensors on a rock glacier during the field expedition. Silwal and her colleagues climbed over rock glaciers with huge boulders and rocky ridges to locate sensors and collect GST data.

The expedition team
Photo: Tika Gurung/ICIMOD

The researchers photographed with porters and mountain guides who play an important role in ensuring the success of an expedition.

Yala Base Camp
Photo: Tika Gurung/ICIMOD

The team camped at Yala Base Camp, at an altitude of about 5,070 masl. Such a glacier monitoring expedition takes about two week to complete, of which a lot of time is spent reaching the research site and acclimatizing to the altitude.