Looking upstream the glacier. Typical for debris-covered glaciers, meltwater has formed large supraglacial lakes on its surface.

I’m placing my foot carefully on a stable rock. This is definitely a terrain to break your ankle. Or, I could slide down with the loose rocks if I create a rock slide on these never ending slopes. When I look back, I see how two people make slow progress behind me, we are all moving together carrying a 40 meter long cable between us.

We move steadily forward without a word. Step by step we go up and down of enormous hills of loose rocks.

Sometimes I can see three people in a line in front of me with another cable, but often we simply have to follow their invisible footsteps as they disappear behind the rocky hills.

Stop, put the cable down, wait for the whistle from the front and forward again.

Luckily, we can measure the thickness of the debris cover with a much smaller system. L – R: Mike McCarthy (British Antarctic Survey), Anna Wirbel (University of Innsbruck) and Ursula Blumthaler.

The landscape could be from the Moon, but we are walking on a glacier. We are measuring the ice thickness on Ngozumpa glacier in Nepal, not so far from the highest mountain in the world. This is the longest glacier in Nepal and large parts of it are covered by debris.  The debris cover can be several meters thick comprising boulders, rocks, sand and silt.

The cable that we are carrying in our hands is a transmitter antenna for ground penetrating radar. The length is necessary to create electromagnetic signals with a low enough frequency, which can penetrate through the debris cover and ice through to the bottom of the glacier where the signal is reflected and received with the receiver antenna carried in front of us.

The work is part of a research project studying the dynamics of debris-covered glaciers in the Hindu Kush and Karakoram Himalayas. The debris-covered glaciers are relatively common in the Himalayas and they behave differently from the clean type of glaciers.

Radar receiver antenna for ice thickness measurements. The entire radar system was about 70 meter long and the measurements required six people.

‘One of the objectives of this project is to better understand how debris-covered glaciers response to climatic variability and their future’, explains the leader of the project Dr Lindsey Nicholson from the University of Innsbruck. ‘This will contribute to the evaluation of future water resources and glacier lake flood hazard potential’.

But first up and go, we have to measure the debris and ice thicknesses!

After several days of hard work, we measured almost five kilometers of ice thickness profiles.  Who would have thought…instead of only rocks, we were walking on hundreds of meters thick ice most of the time!

In March/April 2016, a team of scientists made field measurements on Ngozumpa glacier in Khumbu region, Nepal. The team of scientists were from the University of Innsbruck, British Antarctic Survey, Kathmandu University, ICIMOD and the Bavarian Academy of Sciences. The glacier is about 36 km long and extends from 4700 m up to over 8000 m.

Anna Sinisalo

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