Global Warming Thawing Mountain Peaks And Scientists Are Tracking Growing Rockfall Risks
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One night in July 2018 made Valais canton resident Robert Sarbach feel helpless and terrified. Under a heavy downpour, a chunk of Ritigraben rock glacier broke away, sending waves of debris down to the valley below. It was intense and emotional, Sarbach recalled. In the night, you can see nothing. But you can hear the stones falling, and the water. And you smell the earth.
Scientists do not have much data on rockfalls, partly because they often happen in remote regions where few people live. New technologies are helping to detect more of the bigger rockfalls, though. Seismic sensors clued scientists into an otherwise unreported rockslide in Tibet recently, with an estimated 40 million cubic meters of debris enough to fill about 16,000 Olympic-sized swimming pools crashing down in remote Yarlung Tsangpo. That kind of technology could help detect disasters in the Himalayas, where many of the countries have fewer resources for search and rescue, said David Petley, an Earth scientist at the University of Sheffield who maintains a blog on landslides. In Switzerland, authorities would probably mobilize all resources to help you, Petley said. In Nepal, you are probably on your own.
Still, for years evidence has suggested that landslides are already becoming more frequent. One 2012 study by Huggel and colleagues published in Geology Today found a strong increase in the number of significant Alpine rock slope failures coinciding with warmer temperatures from the 1980s onward. But permafrost covers only about 4 percent of Switzerlands area, which limits the countrys rockfall exposure. In Alaska, where nearly 85 percent of the land contains some amount of permafrost, the danger may be higher.
One area of Alaskas St. Elias Mountains that typically sees six rock avalanches per year on average experienced a total of 41 during the unseasonably warm years of 2013-2016, according to a 2020 study published in the journal Frontiers in Earth Science. Of particular worry are the states coastal mountains, where a mass of rocks falling into the water can trigger big waves. The collapse of a mountain face at Taan Fjord in 2015 dumped a mass of rock into the water, unleashing a 633-foot tsunami in the Gulf of Alaskas Icy Bay, according to the National Park Service.
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https://www.washingtonpost.com/health/as-climate-change-thaws-mountain-tops-risks-of-rockfalls-surge/2021/05/07/b7ac90ca-a369-11eb-a774-7b47ceb36ee8_story.html