Glacier Collapses Are a Growing but Hard-to-Predict Threat

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Neither Maggi nor any of her teammates have been able to visit the site in person because of the risk of further ice falls, as well as the ongoing police investigation. But the statement they issued at the end of their lecture offers perhaps the clearest picture so far of the physical processes behind the collapse.

Identifies a number of contributing factors: the slope of the slope below the secondary peak, Punta Rocca, from which the ice broke; the fact that this section of ice had shrunk so much that it had separated from the main body of the glacier; and the presence of a large crack which, like the perforations of a postage stamp, became the fault line through which the serac sheared.

“What happened, well, what we think happened, because without the possibility of doing a full investigation, we can’t say for sure,” says Maggi, “is that there was an accumulation of water within this crack, which created pressure and pushed until it broke. ”

The media made much of the heat wave before the incident, with temperatures of 10 degrees Celsius recorded near the summit of La Marmolada, at 3,343 meters above sea level, the day before the collapse . But while conditions may have acted as a final trigger, both Italian and international experts warn that not too much importance is attached to the heat of that day or short-term weather patterns. “I think it’s very important to say that’s not the only reason, as it was sometimes reported or hinted at,” says Matthias Huss, a professor of glaciology at ETH, the Swiss Federal Institute of Technology in Zurich. “It was the long-term evolution of this glacier that caused this event.”

Of course, these long-term conditions on glaciers can be controlled. In Huss’s native Switzerland, early warning systems have achieved several notable successes, including predicting, to date, that the Weissmies hanging glacier would collapse in 2017. “They were able to project the dates with relatively high accuracy, so the village downstream of Saas Grund was evacuated only one night, “says Huss.

In Italy, the imminent threat of the Planpincieux glacier in the Aosta Valley region led to the installation of the country’s first visual glacier monitoring system in 2013. Daniele Giordan, of the Italian Research Institute for Geo-Hydrological Protection, whose team designed this, explains that their system is remarkably simple. “We use a Canon DSLR camera, the kind of camera you can buy on Amazon.” This feeds the images to the Turin office, where they are processed by a custom-developed algorithm. “It is a digital image correlation algorithm, from a fairly well-known family of algorithms that can detect motion within a group of images. They are used, for example, to control the speed of cars on intelligent highways. Smart, ”he says.

As the camera began picking up visual clues of a possible collapse, it has since been reinforced with a synthetic aperture interferometric radar, similar to the one used at Weissmies Switzerland, which bounces the ice waves to provide even more accurate readings of potentially dangerous accelerations. of movement. But these systems are expensive.

“The Aosta Valley invested many hundreds of thousands of euros in this monitoring system,” says Giordan. “Maybe 10 times what our initial system cost.” And while the combination has proven to be effective, leading to early warnings in 2019 and 2020, the system, by necessity, is targeted very specifically.

Of course, for a monitoring system to work, “you need to focus on the glaciers, or the area of ​​the glacier, where there may be a collapse,” Maggi says. The problem is that “there are more than 900 glaciers in Italy, and you have to know where to look.”

Most of the glaciers around the world that are currently controlled, Huss explains, have large, obvious seracs, or protruding sections. “Even if you’re not a scientist, you could see how dangerous they can be. But that wasn’t the case with the Marmolada.”

And even if there was a monitoring system, there is no guarantee that it would have detected any revealing movement. “Inside the glacier, there was definitely a lot of water,” Maggi says. “That’s easy to see in the videos. But outside the glacier no one saw more water than you would normally see.” Meanwhile, the crack that flooded and played such a key role in the detachment “was already visible for a few years,” according to the Glaciology Committee statement, and was not seen as disastrous. The cracks, the committee noted, “are a normal part of glacial dynamics.”

This is not to say that any future monitoring effort, whether in the Marmolada or other similar glaciers, would be utterly futile. “I’m not proposing our visual system as a solution,” Giordan says, “but definitely having that data is better than nothing.” He and his colleagues are currently working on a study that suggests their algorithms can provide useful results even when combined with basic webcams.

As glacier retreat worsens around the world, these low-cost solutions could help save lives in countries where budgets are tighter than in Italy or Switzerland, from the Andes to Central Asia. Because, while very little was predictable about the collapse of the Marmolada, the scientists who study these mountains and the guides and guardians who work there agree that these incidents will only become more frequent as the planet warms, and the only way to truly mitigate the The risk goes through comprehensive international action on carbon emissions. “These are the effects of global warming,” says mountain guide Capa Zambanini. “We can say it wasn’t predictable, but that doesn’t mean it wasn’t our fault.”

At the base of the Marmolada, the police incident tape still blocks the way to the top, but the small bunches of flowers left by the bad guys have already begun to wither in the summer heat. The media circus has advanced, and tourists have returned to the terrace of the Cima Undici restaurant. If you had ignored the news cycle, you may be forgiven for thinking that nothing had happened here. Except that from time to time, someone points a phone up, where the deep scar is still too visible, 1,200 feet above our heads.

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