Broken glaciers and overfilled lakes

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.

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 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!