26 July 2021
The rockslide at Batseri in India
It has been a busy weekend for landslide stories to the degree that it’s been difficult to know where to start this morning. However, I have decided it is worth writing about the rockslide at Batseri in the Kinnaur district of Himachal Prrdesh in northern India, the videos of which circulated yesterday.
There are several videos of this event, taken from different perspectives. I think it is worth starting with this one as it shows, right at the start, the source of the rockslide:-
Nine seconds into the video it also shows traffic passing along the road that traverses the slope, of which more later.
These show the dramatic movement of the boulders down the partially forested slope.
And then there is the viral video (which is also in the compilation above), which is best shown in this version:-
The rockslide appears to have started as a result of a collapse on a very steep, rocky outcrop above the bridge at Batseri. The image below shows the terrain using Google Earth. The rock slope has numerous rockslide scars:-
It appears that a mass collapsed, maybe about 700 m vertically above the bridge, and fragmented to generate the “evil dancing boulders”. I have noted previously that the situation in which the boulders start to rotate about a short axis and to bounce is very dangerous. This is the case for numerous boulders here, generating extremely high velocities. Before the bridge is hit one boulder (visible at about 19 seconds into the final video above) takes an enormous bounce due to the terrain:-
The boulder that destroys the bridge also bounced very high, meaning that it impacted the structure in close to freefall. The bridge was unable to withstand the impact.
Unfortunately there is a tragic footnote to this event. A tourist bus was traversing the road at the time of the landslide, and was hit directly by at least one boulder. Nine people were killed and three were injured. Included in those tragically killed was Dr Deepa Sharma, a well known nutritionist with a large following on Twitter. Earlier in the day she had tweeted a selfie of herself standing at the start of the militarised zone along the border with Tibet.
This stands testament to the tragedy of the event.
Many thanks to the various people who brought this to my attention. It is much appreciated.