Glacial moulins: caving deep inside Switzerland's glaciers

In 2012, a team of caver-mountaineers went on a series of expeditions to the glacial moulins of the Gorner Glacier in Switzerland. Serge Caillault talks about both planning the expeditions and the magical world they discovered. A short tale that sheds a little light on the daily "grind" of this extraordinary adventure…

Glacial moulins © Serge Caillault 

An ephemeral and short-lived quest

Exploring glacial moulins combines both caving and mountaineering, two outdoor sports that require solid technical skills. The climate window for this type of exploration is short. You need to know exactly when to seize the opportunity once frigid temperatures start to bring the water flow of glacial streams to a halt. Only during this very short period of time is it possible to descend deep into the glacier without taking too much risk. This includes timing a visit before the first snows cover the glacier in a winter coat that will hide most if not all crevasses from view. This window is extremely short and in some years does not open at all.


Glacier ice holds the world's largest reserves of fresh water…

For example, the more than 3000 glaciers in Kyrgyzstan cover a surface area of 6500 km2. Some of these glaciers have yet to be named. Their slow descent carves out the valleys of the Tian Shan Mountains ("Celestial Mountains" in Chinese).
Experts estimate that these giant rivers of ice lost 25% to 35% of their surface area during the twentieth century due to global climate change. Yet, these reserves of frozen water serve as natural water towers throughout the globe. Those in the Himalaya feed Asia's greatest river systems…

In search of moulins closer to home, let's explore the icy depths of Europe's glaciers.


Glacial moulins, Gorner Glacier, Switzerland

Glacial moulins © Serge Caillault

October is here, and it's time for us to head to our base camp on the Gorner Glacier for one week of exploring the legendary glacial moulins, those underground ephemeral mazes where light and water perform an amazing, yet fleeting dance.
The Gorner Glacier (Gornergletscher in German) is located in the Monte Rosa range, southeast of Zermatt, in the Valais region of Switzerland. Fourteen kilometers long, it is the third longest glacier in Switzerland, behind the Aletsch and Fiesch glaciers. Spanning 1 to 1.5 kilometers at its widest, it covers a surface area of 68 km2, second in the Alps behind the Aletsch Glacier.


Exploration and discovery

This is the third expedition to the glacier for ASV (Vercors Caving Association) and GSM (Fontaine Mountain Caving Group), both from near Grenoble, France. The first expedition took place in 2005, the next in 2010, and the latest in 2012. The landscape has changed each time, making every subsequent expedition as enjoyable as the first. Exploring the glacier never ceases to amaze, with new discoveries made each and every time.
The goal for an expedition is to explore the glacier's deep chasms, to plot GPS waypoints, to map each moulin, and to share this data with the scientific community. The data from one expedition are saved and reused for the following expedition in order to observe how the glacier moves.


The "Jolly Roger"

Glacial moulins © Serge Caillault
Glacial moulins © Serge Caillault

To reach the glacier, we take the train that starts in Zermatt and that climbs to 3089 meters elevation. The panorama is spectacular at the upper station, with views of more than twenty of the Alps' 4000-meter peaks.
After enjoying the extraordinary landscape, we head back down to Rotenboden Station (2815 m). What follows is a three-hour hike with heavy packs to reach the glacier and its moraine. We quickly find an ideal spot to set up camp at 2509 m elevation; home sweet home for the next seven days. Our tents are more or less set up on the ice, even if a thin layer of gravel and dirt provides some insolation for our fragile accommodations. A few well-placed boulders make for a nice rock table and benches. We put the finishing touches on camp by planting the Jolly Roger – our pirate flag. Flying high up on its mast, it provides us with a clearly visible marker for our camp when out on the glacier.
With two hours left until nightfall, a short walk on the glacier is in order. This will allow us to assess our surrounding environment and if possible spot a few entry holes into the glacier. The sunset on Monte Rosa is spectacular. After a night of what can only be referred to as bone-chilling temps, we watch in awe as the sun rises above the Matterhorn. The day starts with promise. 


The "Narrow Moulin"

Exploring begins with a short moulin, christened the "beginner's moulin." All of us descend down a fantastic moulin that Pierre-Bernard and Pascal discovered called the "narrow moulin." Indeed, after a handrail and a 15 meter deep shaft, we continue down a narrow corridor barely one-person wide. In teams of two or three we venture to the siphon that marks the end point of this particular exploration. The journey back to the surface is rather turbulent as the water rises quickly and reaches its high point around 13:00 (the same time every day as it turns out). This proves to be an excellent gauge for the descents we have planned over the next few days. We have to move quickly. With the combined direct sunlight and reflection, the outside temperature easily rises to at least 25°C on the glacier, generating considerable water flow. We need to be efficient as well as prudent when choosing the time of day to explore the moulins. In spite of our fixed gear, a 1°C waterfall pouring down a 10 meter deep shaft onto the head of a caver-mountaineer will turn any pleasant outing into a serious problem pretty darn fast!

Glacial Moulins © Serge Caillault
Glacial Moulins © Serge Caillault

The "Garlic Moulin"

At the end of the following afternoon, after a great day of exploring, Tristan and Alain make a spectacular discovery! It is too late to explore this new moulin, so we make plans to return on Thursday afternoon. This new finding, referred to as the "Garlic Moulin", is located at the end of a glacial stream. The entrance is rather chaotic; the roof collapsed creating huge porch leading to what ressembles a pipe-like tube that plunges 38 meters down, stopping at the siphon. On the other side of the pipe, fallen chunks of ice lay piled up on each other… not reassuring at all!


"The Biggest!"

In the meantime, the rest of the team takes to scouting the glacier by marking the entrances to other moulins… a whole host of pleasant surprises lay in wait for our final day of exploration.
By Friday, there are only four of us left, Emily, Tristan, Alain, and Pascal, with the rest of the team heading back to Grenoble. Although the weather worsens we are no less motivated. Following an afternoon scouting the glacier we know that a gigantic moulin that Pascal and Pierre-Bernard discovered is just waiting to be explored… and it won't disappoint!
The entrance shaft, forty or so meters deep, leads us to a wide tube with a high ceiling, big enough to where we can stand up and practically run! There's little to no water and thanks to the bad weather, there won't be any rise in the water level today. After one hundred or so meters through this beautiful ice cave, we descend a 25 m and then a 10 m shaft one after the other before reaching the bottom, 76.05 m below the surface! We stop at the siphon. The water basin has us wishing we brought our diving gear in order to continue exploring the bowels of the glacier. This is both the deepest and the most beautiful moulin we explored this year! We name it, "The Biggest!" Sure, it is nowhere near as deep as its more than one hundred meter deep big brother located inside the Mont Blanc range's Mer de Glace, but it has nothing to be jealous of in terms of beauty.


An international adventure

Glacial moulins © Serge Caillault


The week ends and we break camp on Saturday morning during a snowstorm. On the hike out, we cross paths with three well-equipped Welshmen carrying huge backpacks. Intrigued, we asked them what they plan on doing in the area. They have plans to camp for seven days on the glacier in order to explore and to go diving in the moulins! Five other people will meet up with them the next day… We wish them best of luck, especially since the weather forecast for the week is not very good.

One week later we receive an email from one of the Welshmen to learn that it snowed 60 cm in three days. In the end, they had two days of calm weather to explore two moulins before it started snowing again. They were unfortunately unable to complete their entire project.
It doesn't matter. Like us, they plan to go back… Perhaps marking the beginning of an international adventure!

Note: this expedition was organized by ASV (the Vercors Caving Assocition) and GSM (the Mountain Caving Group). Eight people participated: Émilie Rebreyend, Isadora Guillermo, Tristan Godet, Pierre-Bernard Laussac, Serge Caillault, Alain Maurice, Pascal Guinard and Anthony Brigant. Clotaire Michel, a scientist friend who works at a laboratory in Zurich, joined us that Thursday to spend the day with us.

Glaicial moulins © Serge Caillault


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