Natural disasters

Geomorphology is mostly a multi-millennium scale business, but sometimes landscapes change dramatically in a few hours. When this happens in remote mountain regions, publicly available satellite imagery can be very useful.

Glacier hazards

Bashkara Glacier lake outburst

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Sep. 5, 2017

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Aug. 26, 2017

Contains modified Copernicus Sentinel data (2017). Processed with SentinelFlow.

On 1st September 2017, an ice-dammed lake by Bashkara Glacier in the Caucasus drained catastrophically resulting in several road cuts on the main road leading to Mount Elbrus, temporarily isolating mountain towns and several groups of mountaineers. From these images it seems that water from the upper lake spilled over the glacier and eroded its way to the lower lake through the upper layer rock deris and the underlying ice. The lake outburst generated a debris flow that provoked road damage and river terrace erosion visible on these images at least 50km downvalley. The event has been documented by the Russian media and social networks.

Saldim Peak outburst flood

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May 8, 2017

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Apr. 4, 2017

Contains modified Copernicus Sentinel data (2016). Processed with SentinelFlow.

On 20th April 2017 a rockslide on the west face of Saldim Peak in Nepal Himalayas provoked a moraine breached and outburst of knowingly dangerous glacial lake. The subsequent debris flow extended far down in the valley where significant erosion and vegetation trimming is visible on the images. Read more about it here.

Aru Co twin ice avalanche

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Nov. 18, 2016

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Jan. 23, 2016

Contains modified Copernicus Sentinel data (2016). Processed with SentinelFlow.

On 17 July and 19 September 2016 a double collapse of two entire glacier Tongue near Aru Co in Tibet puzzled glaciologists as no similar event had been recorded before. Following the first avalanche and using satellite imagery researchers could predict the second collapse roughly at the time it occurred. Read more about it here.

Rockfall hazards

Pizzo Cengalo rockslide

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Aug. 25, 2017

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Aug. 15, 2017

Contains modified Copernicus Sentinel data (2017). Processed with SentinelFlow.

On 23 August 2017 a rockfall occurred on the north slope of Pizzo Cengalo in south-eastern Switzerland. An impressive quantity of rock fell in Val Bondasca (centre right), and debris flowed further along the river course, destroying large parts of the village of Bondo (top left). Sedimentation is visible on these images further downvalley to the lake in Ponteggia more than 11 kilometres downstream from the source area.

Xinmo rockfall

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Sep. 7, 2017

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Feb. 9, 2017

Contains modified Copernicus Sentinel data (2016). Processed with SentinelFlow.

On 24 June 2017 a massive rockfall occurred in Maoxian County in the Sichuan province of China. Unfortunately the event was a real tragedy as many homes were buried under a thick layer of debris. The river was not dammed by the rockslide but instead appears to have taken a new course over the debris. Read more about it here.

Lamplugh Glacier rockfall

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Nov. 18, 2016

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Jan. 23, 2016

Contains modified Copernicus Sentinel data (2016). Processed with SentinelFlow.

On 23 June 2016 a major rockfall, possibly the largest captured by Sentinel-2 satellites to date, occurred on the Lamplugh Glacier in Glacier Bay, Alaska. The rockfall was recorded by seismometers as a 2.9 magnitude earthquake. These images reveal that rock debris flew upslope into tributary valleys and extended as far as 10.4 kilometres away downstream from the source area despite of the very gently sloping glacier surface.

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Nov. 18, 2016

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Jan. 23, 2016

Contains modified Copernicus Sentinel data (2016). Processed with SentinelFlow.

A zoom onto the source area of the rockfall shows that a supraglacial lake formed temporarily at the edge of the debris-covered area. A minor landslide occured on the southern side of the mountain while the main crest shifted about 100 metres to the south. Read more about the Lamplugh rockslide here.