Update 2025-06-03: Now with a photo of two actual 3D prints.
Even if you don't live in Switzerland, you've probably heard the news about the now-collapsed Birchgletscher. Quoting from ETH's fact sheet from June 2nd:
[...] On Wed 28.05.2025, ~15:30 CEST, the glacier known as Birchgletscher (Valais, Switzerland), collapsed under the weight of the rock-debris that had accumulated on its surface due to a series of rock avalanches originating from Kleines Nesthorn, a mountain peak that became unstable in the course of the preceding week. [...]
Since a couple of years ago, events like this have been monitored by the federal Rapid Mapping service, which is owned by the Federal Office of the Environment (German: BAFU) and operated by Swisstopo. Immediately after Wednesday's event, the Rapid Mapping team collected new data by flying over the area aircrafts. And, as Ralph wrote on spatialists.ch,
[...] Thanks to the open nature of the Rapid Mapping data and the expertise of individuals, textured 3D models of the affected area have been quickly built and published [...]
One of these individuals is Simeon Schmauß, who reconstructed a post-event elevation model using the photogrammetry software Metashape, utilizing oblique aerial images from May 30th. Simeon has not only published the data but also shared an annotated post-event 3D model, which I highly recommend exploring yourself.
The size of the affected area is astounding—approximately 10 million cubic meters of rock debris flowed. As the fact sheet states, "[...] At the scale of the Swiss Alps, the recent event is unprecedented. This is true for both the dynamics and the impact of the rock-ice avalanche."
As always, it's tough for us to think about and grasp such large-scale events. So, maybe it helps to focus on the local impact. To do that, I modified the Topoprint processing pipeline to optionally include Simeon's photogrammetric DEM and calculated Topodiscs for two example areas:
- "Before" and "After" for an example close to the edge of the debris. After the avalanche, some buildings are still visible. The maximum change in elevation is 18 meters.
- "Before" and "After" of an area where all buildings had been buried - the maximum change in elevation is 28 meters.
Click on the links above to explore the area in 2D and 3D. From there, you can also print the model - either with your own printer or using a print-on-demand service.
For both calculations, I used the photogrammetric DEM of the Blatten glacier collapse, created by Simeon Schmauß from swisstopo/BAFU Rapid Mapping oblique imagery: CC BY 4.0 - thanks Simeon!
Small reliefs are a great way to get a grasp of the bigger picture by seeing and literally feeling the details (you can print the reliefs directly from the example links above). They remind us that even massive events become easier to understand when we look closely.
In this spirit, please consider donating to a good cause, whether it’s for the people in Blatten, to promote greater awareness in Switzerland, or to support worldwide initiatives like the Climate Justice Alliance.