24 February 2016

Annapurna: a large rock avalanche on 23rd Feb?

Posted by Dave Petley

Annapurna rock avalanche

Various news agencies in Nepal are reporting that there was a large dry landslide, which will mean a rockslide, in the Annapurna area of Nepal yesterday.  For example, Republica reports the event as follows:

The massive landslide that hit Narchyang area near the Annapurna South Peak in Myagdi district at around 3 am on Tuesday caused a magnitude 3.8 tremor, according to the National Seismological Center (NSC).  “The dry landslide produced a magnitude 3.8 tremor. Small landslides do not create tremors of this magnitude,” said Lok Bijaya Adhikari, chief of the center…Thick clouds of dusts produced by the continuous landslides have affected normal life in Narchyang, Dana, Bhurung, Tatopani, Shikha, Ghar and Dowa VDCs. DSP Bishwa Raj Khadka, chief of District Police Office (DPO), Myagdi, informed that Nepal Army and Police personnel are having difficulties reaching the uplands due to the thick dust and haze.

All the indications are that this was a very large landslide – the dust plume, reports that it has blocked the valley and of course the detection of a seismic signal.  As yet there are no images, but reports suggest that the Ghalmedi Kola (river) has been blocked.  I believe that this is the channel in the centre of this Google Earth image (NB this is a correction from earlier after further research):



The Ghalmedi Kola in the Annapurna area of Nepal via Google Earth


News reports suggest that a team has been dispatched to take a look, so hopefully more information will emerge in the next few days.  Sadly the seismic event associated with this landslide is too small to have appeared in the online seismic catalogues as far as I can tell.  In the image above there are various locations in which a large slope failure could have occurred.

There were news reports yesterday that five people were missing in this landslide, but these individuals have now reappeared.