How wet is the snow?

Early start of the monsoon challenges Langtang Hydromet Fieldwork

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Glacio-hydrologist Maxime Litt approaching Ganja La Pass through a foot of fresh snow. Yala glacier can be seen below the second peak from the top left Photo credit: Inka Koch/ICIMOD

He pulled the string of the generator one more time, It did not move an inch. Not only was the machine stuck, so were we. Fieldwork is not like in the old days any more where a tape measure and notebook were enough. Now we bring drones (unmanned aerial vehicles) with us to remote areas and have an array of automatically recording instruments that need to be powered. Data is not recorded by hand any more, data is electronically transferred onto our notebooks and backed up on external hard drives. So, without a power source, our presence in the mountains is basically pointless. On the other hand, it is almost a rule that something will break in the field. As a consequence, one either prepares for backups or slowly turns into MacGyver; making seemingly broken things do their trick again. A few hours later, we had thus organized an alternative power source and were ready to face anything. 

It is not just gear back-ups that are required in the field, it is also advisable to have more than one person who knows how to execute a particular task in one team because brain capacity severely decreases at high altitudes. Faced with wet and adverse weather conditions this year, it was a challenge for the field crew to stay healthy. It was only April, but it seemed like monsoon was here early. Colds and stomach bugs so tenacious they would not heal during three weeks of fieldwork knocked many of our field team members out in turns. Added onto that was the challenge of navigation in rough mountain terrain. By day three, a third of our team was either injured or sick. Remarkably enough, endurance and the curiosity to execute scientific tasks prevailed within the field team and we successfully accomplished all the tasks we had initially planned for.   

Sensor measuring snow water equivalents at Yala Glacier Base Camp. 
Photo credit: Maxime Litt/ICIMOD

Langtang Valley is specked with automatic weather and hydrological stations recording meteorological variables and discharge. Furthermore, mass loss of debris-covered glaciers is monitored and snow samples are taken. All this, in an attempt by the International Centre for Integrated Mountain Development (ICIMOD), the University of Utrecht, and the Norwegian Water Resources and Energy Directorate to better understand patterns of snow and ice melt and its contribution to river runoff. The maintenance and monitoring of these stations requires that data records be kept gap-free and that field staff walk up the slopes of the valley covering a total distance of more than 70 km, on and off track. This year, it did not cease to snow, and we had to navigate the technical Ganja La Pass through a foot of snow- scenic for the eyes, challenging for the feet. 

All set to work on an automatic weather station on Yala glacier, author with Research Associate Tika Gurung (standing). 
Photo credit: Maxime Litt/ICIMOD

This snow, though, is exactly what we are interested in monitoring. Thus, the University of Utrecht just invested in a sensor that measures how wet the snow is (i.e., how much water would result from the melt of the whole snow pack). This system, the second of its kind in Langtang Valley was assembled close to Yala Glacier from parts that were carried by a group of porters to an altitude of 5,100m. The timing of snow events is further recorded by an on-glacier automatic weather station that has now recorded standard meteorological variables for more than one year as well as snow depth and air turbulence. The turbulence measurements will help to evaluate how much snow/ice does not melt but sublimates (i.e., changes phase from solid to gas) in the dry high altitude air. This phase change also cools down the snow/ice and influences the direct transfer of heat from air to snow. Snow depth measurements will help to evaluate the exact timing of snow events that brought pollution to the glacier. Dark particles from incomplete combustion (i.e., black carbon) change the albedo (reflectivity of the snow) and thus promote melting of the snow. 

Navigating Ganja La Pass: Scenic for the eyes, challenging for the feet.
Photo credit: Inka Koch/ICIMOD

With all field data backed up onto external hard drives and later into the cloud, and brain capacities returning to normal at low altitudes, the field team has now returned to their offices in Kathmandu and Utrecht, to analyse and write up the data. Looking at the field photographs, biased to times when it was dry enough to take the camera out, makes us already long for the next field trip in autumn. 


Comments

Jeffrey S. Kargel wrote on 2017-06-22 20:38

I am so glad to see research continuing in Langtang Valley even after all the tragedy there and also after losses of equipment. That is called perseverance in pursuit of knowledge and understanding. That is a deep commitment to science and to people. This writeup was a very nice, plainly/clearly written explanation of what you are doing; and at the same time it is also a helpful description for scientists.