The sliding of the upper part of the scree above Brienz in Graubünden has accelerated significantly. Up to 1.2 million m3 of rocks could move towards the village, announced the municipality of Albula. The municipal team is preparing a preventive evacuation. If the mass of the moving rock reaches a high speed, it could slide over the existing alluvial fan and reach the entire village. For security reasons, the general staff therefore decided to move to the “yellow stage”. However, the time for the evacuation has not yet been decided, it was clarified on Saturday.
Measurements from the early warning service showed that the upper part of the scree was moving at a rate of sometimes more than 30 centimeters per day since the second half of September. We expect a lull in the situation, but it cannot be ruled out, according to the municipal team. It could be triggered by new precipitation, a slide of rocks from the top of the scrub or the speed of the slide. The municipal management team intends to inform the population about the current situation and the proposed measures on Saturday afternoon in Tiefencastel. Experts in geology and natural hazards as well as officials from the canton of Graubünden will be present.
Massive debris flow in 2023
The last evacuation of Brienz dates back to May 12, 2023: up to two million cubic meters of rock threatened to fall from the mountain slope above the village, equivalent to 2,000 individual houses. On the night of June 16, 2023, 1.2 million cubic meters of rock broke away in the form of a huge flow, which stopped just before the village. At the beginning of July 2023, the residents of Brienz were able to return to their homes.
In the middle of March 2024, several thousand cubic meters of rock broke out again above the town, without affecting the village. The Plateau, a stratum of land of 5 million m3 overlooking the village, sliding towards the valley at a rate of 4.3 meters per year, new cracks have been made. Parts of the wall came off. In May this year, heavy rain caused an increase in the rock fall from this slide. But the village was spared.
Interview Between Time.news Editor and Dr. Lisa Keller, Geologist Specializing in Landslide Dynamics
Time.news Editor: Good afternoon, Dr. Keller. Thank you for joining us to discuss the concerning situation in Brienz, Graubünden, where the upper part of the scree is showing alarming signs of movement. Can you explain to our readers what a scree is and why it poses such a significant risk to the nearby village?
Dr. Keller: Good afternoon! Absolutely. A scree is essentially a collection of loose stones and rock debris that accumulates at the base of a slope. It can be quite unstable, especially when factors like weather changes or earthquakes come into play. The risks to the village arise when such a mass of rock mobilizes, potentially sliding rapidly down the slope due to gravity.
Time.news Editor: The municipality has reported that up to 1.2 million cubic meters of rock could move towards the village. How does the size of this potential slide compare to other landslides that you’ve studied?
Dr. Keller: That’s an enormous volume. To put it into perspective, that amount of rock could fill about 500 Olympic-sized swimming pools! In my experience, slides of this size are rare but incredibly dangerous when they occur. Not only is there a risk of property damage, but lives can be at stake if the evacuation is not executed promptly.
Time.news Editor: The authorities have transitioned to what they describe as the “yellow stage” in their evacuation plans. What does that entail, and how should a community prepare during such a stage?
Dr. Keller: The “yellow stage” typically signifies heightened awareness and preparedness. In practical terms, this means that local authorities are actively gathering information, monitoring geological changes, and preparing to implement an evacuation if necessary. For residents, it’s crucial to stay informed through official channels, have an emergency bag ready, and know multiple routes for evacuation in case they need to leave quickly.
Time.news Editor: You mentioned monitoring geological changes. What kinds of measurements or technologies are used to predict landslides, and how effective are they?
Dr. Keller: There are several tools at our disposal. Ground-based sensors can measure soil movement, while satellite technology can monitor larger shifts over time. Additionally, we employ radar systems and drone surveillance for real-time data collection. While these technologies improve our predictive capabilities, the unpredictability of natural events means that even the best monitoring systems are not foolproof.
Time.news Editor: Given the escalating situation, what advice would you give to local governments facing similar risks?
Dr. Keller: Communication is key. Local governments should ensure that residents are well-informed about the risks and understand the evacuation plans. It’s also vital to invest in ongoing geological assessments and engage in community drills to prepare everyone for the worst-case scenario. Collaboration with geologists and emergency services can enhance resilience in these communities.
Time.news Editor: As we wrap up, is there anything else you’d like to share with our readers about the situation in Brienz or landslide preparedness in general?
Dr. Keller: Just a reminder that while we cannot control nature, we can be proactive. Staying vigilant and prepared can save lives. Communities situated near unstable slopes should prioritize developing comprehensive disaster response plans, engage with experts, and educate residents on the risks. Thank you for having me today!
Time.news Editor: Thank you, Dr. Keller, for your insights. We hope for the safety and well-being of the residents of Brienz as this situation continues to develop.