Monday, July 8, 2013

A scar on Annapurna that had caused the Seti Flood of 2012

I had been going through different articles and papers about the Seti Flash Flood of 2012 and, I wanted to try out something for myself.

On May 5th of 2012, a flash flood full of debris, triggered in the Seti river, had devastated different parts of Pokhara with an estimated 71 people killed. A unique thing about this flood was that, it was probably triggered by an avalanche near the Annapurna range. This triggering of the avalanche was actually captured in tape by a Russian pilot who was flying over the same area at the time of avalanche, and about 40 minutes after the avalanche, the devastating  flood hit Pokhara. One of the most comprehensive reports on the cause of the flood should be the report prepared by Dr. NP Bhandary, Dr. RK Dahal and Prof. M Okamura based on their field visit (Bhandary et al. 2012).

Initial speculations on what might had caused the flood ranged from intensive rainfall-cloudburst flood, possible GLOF (Glacial lake outburst flood) as well as LDOF (Landslide Dam Outburst Flood). But no significant evidences supporting the latter two were found in the field. Also, the flood had occurred way before the monsoon, reducing the possibility of cloudburst flood . Looking at the devastation and magnitude of the flood, initiation of such a flood would require a huge source of water (millions of cubic meters) and these speculations couldn't properly explain the source of such a huge quantity of water.