Glacial collapse is a growing but difficult to predict threat

Because of the threat of further ice falls and the ongoing police investigation, neither Maggi nor any of his colleagues were able to visit the site in person. But the communiqué they released at the end of their conference offers perhaps the clearest picture yet of the physical processes behind the collapse.

It identifies a number of contributing factors – the steepness of the slope below the secondary peak, Punta Rocca, from which the ice has broken off; the fact that this section of ice had shrunk to the point where it had separated from the main body of the glacier; and the presence of a large fissure, which, like perforations on a postage stamp, became the fault line along which the serac sheared.

“What happened — well, what we think happened, because without being able to do a full investigation, we can’t say for sure,” Maggi says, “is that water has accumulated in that fissure, causing pressure and.” Pressure generated pressed until it collapsed.”

Media reports have talked much about the heat wave leading up to the incident, with temperatures of 10 degrees Celsius recorded the day before the collapse near the summit of the Marmolada, 3,343 meters above sea level. But while conditions may have served as a final trigger, both Italian and international experts warn against over-emphasizing the day’s heat or short-term weather patterns. “I think it’s quite important to say that this is not the only reason, as has sometimes been reported or implied,” says Matthias Huss, professor of glaciology at ETH, the Swiss Federal Institute of Technology in Zurich. “It is the long-term evolution of this glacier that caused this event.”

Of course, such long-term conditions can be monitored on glaciers. In Huss’ native Switzerland, early warning systems have achieved several notable successes, including the accurate prediction to the day that the hanging glacier at Weissmies would collapse in 2017. “They were able to predict the date with a relatively high accuracy, so the downstream village of Saas Grund was only evacuated for one night,” says Huss.

In Italy, the looming threat of the Planpincieux glacier in the Val d’Aosta region led to the installation of the country’s first visual glacier monitoring system in 2013. Daniele Giordan of the Italian Research Institute for Geohydrological Protection, whose team designed it, explains that his system is remarkably simple. “We use a Canon DSLR, the kind of camera you can buy on Amazon.” This transmits images to the Turin office, where they are processed by a proprietary algorithm. “It’s a digital image correlation algorithm — one of a fairly well-known family of algorithms that can detect movement within a group of images. They are used, for example, to control the speed of cars on smart highways,” he says.

As the camera began to capture visual clues of a possible collapse, it has since been assisted by an interferometric synthetic aperture radar – similar to that used on the Weissmies Switzerland – which bounces waves off the ice for even more accurate readings of potentially dangerous accelerations to deliver the movement. But such systems are expensive.

“Val d’Aosta has invested many hundreds of thousands of euros in this surveillance system,” says Giordan. “Maybe 10 times what our original system cost.” And while the combination has proven effective, leading to early warnings in 2019 and 2020, the system is necessarily very targeted.

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

Most glaciers around the world that are currently being monitored have large and obvious seracs, or overhanging sections, according to Huss. “Even if you’re not a scientist, you could see how dangerous they could be. But that was not the case with the Marmolada.”

And even if a surveillance system had been in place, there’s no guarantee it would have detected telltale movements. “There was definitely a lot of water inside the glacier,” says Maggi. “It’s easy to see in the videos. But outside of the glacier no one saw more water than would normally be seen.” Meanwhile, according to the Glaciological Committee, the flooded fissure that played such a fundamental role in the detachment had “been visible for several years” and was not considered threatening viewed. Crevasses, according to the committee, “are a normal part of glacial dynamics.”

That’s not to say that any future surveillance efforts – either on the Marmolada or other similar glaciers – would be entirely futile. “I’m not proposing our visual system as a solution,” says Giordan, “but having this data is definitely better than nothing.” He and his colleagues are currently working on a study that suggests their algorithms, even when combined with simple ones Webcams can provide useful results.

As glacier retreat worsens worldwide, such low-cost solutions could potentially help save lives in countries where budgets are tighter than Italy or Switzerland, in mountain ranges from the Andes to Central Asia. Although very little could have been predicted about the collapse of the Marmolada, the scientists who study these mountains and the guides and guardians who work within them agree that such occurrences will only become more common as the planet warms – and the only way to really mitigate this risk is through comprehensive international action on CO2 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 foot of the Marmolada, police tape still blocks the way to the summit, but the small bouquets of flowers left by mourners have already begun to wither in the summer heat. The media circus has moved on and tourists have returned to the terrace of the Cima Undici restaurant. If you had ignored the news cycle, you could be forgiven for thinking nothing happened here. Except every now and then someone points a phone up to where the deep scar is still all too visible 1,200 meters above our heads.

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