What truly brought about Dharali flash flood: An avalanche of 360 million cubic metres of glacial particles

A preliminary geological evaluation performed after the devastating flash floods in
Dharali village revealed that a much more complicated and large collapse of glacial sedimentary deposits brought about the floods within the area. In line with a report by The Occasions of India, retrogressive slope failure excessive up within the mountains brought about the collapse of the sedimentary deposits.

The knowledgeable laid out the possible trigger by drawing preliminary estimates based mostly on satellite tv for pc information and terrain evaluation. The specialists pointed to an avalanche of almost 360 million cubic metres of particles as a explanation for the flood.

The Dharali village was finally not capable of stand up to the excessive drive, which in the end brought about heavy devastation within the area. Specialists advised TOI that the avalanche was mobilised by a sudden launch of unstable morainic and glacio-fluvial materials, thundering down the Kheer Gad stream into Dharali.

The strain was so intense that the surge reached the village inside a number of seconds, destroying over 20 constructions and claiming the lives of no less than 4 folks. Imran Khan, geologist and head of the geology division at Bhutan’s Punatsangchhu-I hydel venture, advised TOI that the satellite tv for pc photographs of the realm don’t mirror that it was a typical cloudburst.

“The occasion seemingly concerned a large detachment of unconsolidated glacial deposits, perched roughly 7 km upstream at an elevation of 6,700m. Heavy rainfall might have acted because the set off, however the catastrophe was ready to occur,” he advised the Indian information outlet.

In regards to the glacial deposit within the area

In line with TOI, the glacial deposit in query spans over 1.1 sq km with an estimated vertical thickness of 300m and is understood to be an inherently unstable geological characteristic. After the glacier deposit’s fall, the excessive terrain within the area accelerated the pace of the particles, leaving just about no time for the residents to flee.

“The stream draining this space has a excessive longitudinal gradient, restricted lateral confinement, and sharp incision paths-all of which contribute to speedy particles move mobilisation,” Khan advised TOI, including that floor runoff and percolation, following days of intense rain, might have loosened the sediment, triggering the collapse.