{"id":20165,"date":"2016-10-24T07:21:49","date_gmt":"2016-10-24T07:21:49","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=20165"},"modified":"2016-10-24T07:21:49","modified_gmt":"2016-10-24T07:21:49","slug":"tibet-avalanches-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2016\/10\/24\/tibet-avalanches-1\/","title":{"rendered":"The mysterious Tibetan ice avalanches of summer 2016"},"content":{"rendered":"
The mysterious Tibet avalanches of summer 2016<\/h5>\n

At the start of the summer, a somewhat mysterious giant ice avalanche occurred in the Aru mountains above Lake Aru Co, the first of a pair of Tibet avalanches in this region.\u00a0 This was covered by Xinhua, with a strong sense of surprise<\/a>.<\/p>\n

The avalanche in southwest China’s Tibet Autonomous Region on Sunday was a glacier slide, it has been confirmed.\u00a0 A 600-meter rescue passage had been completed Wednesday morning, but no signs of life have been detected.\u00a0 Nine people, buried by the icefall in Dungru Village in Rutog County, Ngari Prefecture, on Sunday, were confirmed dead on Monday. … “Rescue work is continuing, while the cause of the ice avalanche is being investigated to avoid secondary disasters”, said Zhang Jianping, a police officer directing the rescue.\u00a0 UAV aerial images show that the icefall took place between glaciers on two snow-capped mountains at an altitude above 6,000 meters.<\/p><\/blockquote>\n

CriEnglish<\/a> included some images of the avalanche:<\/p>\n

\"Tibet

One of the Tibet avalanches, via Cri-English<\/p><\/div>\n

.<\/p>\n

It is hard to fathom this size of this event, but satellite images help.\u00a0 The European Space Agency imaged it with the EOI instrument, generating this before and after pair of shots (via NASA<\/a>):<\/p>\n

\"Tibet

The first of the Tibet avalanches, imaged by the EOI instrument (via NASA<\/a>)<\/p><\/div>\n

.<\/p>\n

This is a very large event – estimated at 60 million cubic metres and with a deposit that covers some 10 square kilometres.\u00a0 Few such events have been previously described, so their mechanisms are poorly understood.\u00a0 The Atlantic<\/a> has a really nice article about this event, highlighting the work of Andrea Kaab at the University of Oslo, who has been investigating it.\u00a0 This includes a nice image of the source area, captured by Planet<\/a>:<\/p>\n

\"tibet

The source area of the first of the Tibet avalanches, via Andreas Kaab and The Atlantic<\/a>.\u00a0 Image collected by Planet<\/a><\/p><\/div>\n

.<\/p>\n

But there is another really surprising aspect of this event, as The Atlantic<\/a> describes:<\/p>\n

This Planet imagery revealed new aspects of the Tibetan glacier. Before the Aru glacier failed, it looked like it was about to surge. Water pooled on its surface, and crevasses started to appear. Surging, though, is a regular part of a glacier\u2019s life. Why had the Tibetan glacier failed catastrophically and not started surging like it should have?<\/p>\n

For now, this question will require further study. More worrying was a feature that K\u00e4\u00e4b noticed in a Sentinel-2 image, something to the south of the avalanche\u2019s debris field. Another glacier had started exhibiting the same characteristics as the Tibetan glacier which collapsed. It showed large crevasses. Would it collapse as well?<\/p><\/blockquote>\n

This second glacier collapsed on 21st September, generating another enormous avalanche deposit.\u00a0 Planet<\/a> has a high resolution image of this second event; the edge of the remains of the first deposit are just visible at the top of the image:<\/p>\n

\"Tibet

The second of the Tibet avalanches, image by Planet<\/a><\/p><\/div>\n

.<\/p>\n

The one such event should occur is remarkable; two is unprecedented.\u00a0 In fact the second avalanche look to me to be two separate events, the larger of which occurred first, based on the apparent presence of two deposits in the above image.<\/p>\n

The most likely explanation for the Tibet avalanches, and the associated glacial collapse, is climate change.\u00a0 That Tibet is warming rapidly, and that the glaciers are retreating rapidly in response, is well-established.\u00a0 This style of extreme mass movement appears to be a rather dramatic, and worrying, response.<\/p>\n

Previous posts that might be of interest<\/strong><\/h5>\n