Broken glaciers and overfilled lakes

by Johannes Landmann & Christophe Ogier, glaciologists at ETH Zurich, 19 November 2020

Join two young glaciologists on their field trip to two glaciers in Switzerland. Field work is an essential part of research on glaciers: it’s marvellous, but can tax your patience.

Tuesday, 4 August 2020, 4.30 p.m., somewhere in the sea of tail lights on the highway between Zurich and Bern. We, that’s scientific assistant Christophe Ogier and doctoral student Johannes Landmann, didn’t know at that time that it would take us more than five hours to get from Zurich to the first of our two field trip stops: Zermatt.

Our two-day mission goal is to contribute a little field work piece to a big scientific puzzle. We would maintain and redrill the ice melt stakes of our near real-time glacier melt camera stations on the glacier surface. These stations allow us to retrieve daily estimates of ice loss for one point in space. We then assimilate these estimates into a bigger ensemble modelling framework, which can help us to better manage future water shortages caused by the shrinking glaciers in our country.

Johannes taking the “Findelengletscher glacier fore-field challenge”: Finding a path through this some-times unstable area can be difficult. It’s made up of loose rocks, little streams, dead ice and mud; the glacier itself was right here only a few decades ago. (photo credit: Christophe Ogier/ETH Zurich)

After a (too) short night, we’re already on the way to our first destination of the day: Findelengletscher, a majestic Alpine glacier to the east of Zermatt. After taking a cable car and then descending over a steep moraine, we reach the glacier forefield, which is longer and more difficult to cross every time we return to the spot. Huge rocks and streams mix with soft mud and dead ice – we are constantly searching for a new path through this recently exposed glacier bed. We are shocked to realise that the glacier tongue has started collapsing, giving an impression of textbook blue ice blocks. When getting the camera station at the tongue of the glacier ready for the next year, we’re hit by a flush of fresh air after drilling through only 3m of ice. We’ve unfortunately drilled in a pressurised air cavity (!) – a harbinger of the total glacier tongue collapse which would follow in the summer.

The glacier tongue of Findelengletscher showing first signs of imminent collapse. (photo credit: Christophe Ogier/ETH Zurich)

This stake length shows the amount of ice melt that occurred between June and August 2020 at the tongue of Findelengletscher. (photo credit: Christophe Ogier/ETH Zurich)

The glacier-dammed lake on Plaine Morte. This lake started to empty by flowing through the glacier only a few hours after our visit. (photo credit: Christophe Ogier/ETH Zurich)

In the hot noon sun, we ascend to the second station at 3020m above sea level. This needs some maintenance too, since even at these heights, melt has changed the glacier more than we anticipated. Along the way, we find a cluster of birthday balloons, a sign of mankind even in this hostile terrain.

After a quick “summit” lunch, we head straight back to the cable car, otherwise we would miss the last one and have to descend an extra 1500m ourselves. We treat ourselves to a quick shot of caffeine so as not to fall asleep during the car ride to our next destination: Sion. We’ll spend the night here before redrilling another station on a different glacier: Glacier de la Plaine Morte. Measuring some 7km2, this glacier is the largest plateau glacier in the Alps.

We drill and insert a new, 7m long stake into the ice to measure glacier surface melt in the coming year. Plaine Morte glacier. (photo credit: Christophe Ogier/ETH Zurich)

We stay overnight at a friends’ place to have a good time and… well…be gentle with our project resources after all. At around 9 p.m. we finally get around to dinner, before having to prepare the field work of the next day.

We’re happy that the ascent to Glacier de la Plaine Morte is even more comfortable than Findelengletscher: the cable car drops us at a ridge close to the glacier, and climate change lets us descend around 150 vertical metres to the glacier surface. Walking on the glacier is also easier here than at Findelengletscher, despite some slushy fresh snow from the last few days. We not only get our camera station ready for the whole of next year with a monstrous 7m long stake, but we also monitor a periglacial lake dammed by the glacier, which is about to burst and might put the community of Lenk further downstream in danger of flooding. The previous year, a trench was dug at the ice surface to empty the lake into a natural glacier moulin – before it would drain through the glacier naturally. The trench seems to be blocked this year though; we barely see any runoff, and we’re concerned about a sudden outburst. However, it seems we were one day early: on the day after our field trip, the lake starts running off, with luckily no damage for the population downstream.

We run back to the cable car station to catch the last cable car, not knowing that we would once again spend 5 hours in the car to Zürich – this time, because a train at the Lötschbergtunnel was cancelled. That’s a lot of events for a tiny puzzle piece!

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About the authors

Johannes Landmann studied geography and meteorology at the Universities of Bonn, Germany, and Innsbruck, Austria. He is currently pursuing a doctoral degree in glaciology at ETHZ, focusing on near real-time glacier ensemble modelling and data assimilation techniques.

Christophe Ogier studied climate sciences at University of Grenoble-Alpes, France and is also a mountain guide. He is currently employed by ETHZ as a scientific assistant to work on different glaciological related-topic.